I have been a frustrated owner of a 9mm AR for years! It took a lot of time and research to get my 9mm AR running reliably. I am glad to see that you are putting all the important information in one place for future 9mm AR owners to find easily. I wish your page existed ten years ago.
I haven’t watched this video yet, but judging by this dudes work bench and 5 seconds of his voice, I am 100% confident he knows exactly what he’s talking about.
Damn. I’ve been chasing my ejection issues the past two range sessions. My ejector was a point and at the bottom of the bolt. Squared it off, moved up and in and never ejected better. Thank you sir.
I was having ejector issues with my AR-9, it was low but I recently adjusted it to how you showed. Haven’t got to test it out yet. Great video and information
I swear now that I've figured the feed ramp out after finding a single video with very specific and extensive key word searches on multiple apps, youtube has decided I'm allowed to see the pantheon of videos that I looked for initially many moons ago. You're doing the community a great service sir. Sorry for being years late to the party, i was caught in algorithm traffic.
Helpful info. I got lucky!!! I purchased a built Foxtrot Mike AR9 upper and then their factory built lower separately. I put the 2 together and it’s been 100% reliable from day 1. After adding a suppressor, all I had to do is add a heavier buffer. (45ACP) 7.50oz Going to hit the range today!!! Enjoyed the vid.
I’ve reviewed your website in addition to watching your videos. I think I’ll get a Kynshot hydraulic buffer. V’s the KAK. What’s better….. RB5000HP with 2 extra weights or the RB5015HD with 1 extra weight? For now I will assume it’s the RB5000HP because it adds up to more total mass. Thanks.
You're right, the 5000HP + 2 has better felt recoil. For the correct 9mm bolt travel, they need to be paired with an A5 length buffer tube (7.75" internal). @@scott2228
This is the rout I’ll go. I can’t go longer than A5 bc the gun would no longer fit in it’s dedicated range bag. Lol. A5 will b right. Thanks for all ur help.
I really appreciate all of your research! I was able to build my 9mm AR upper with 100% function and reliability first try with your info and reply's. Here is my build for anyone wondering: BKings Bolt Carrier Group, BKings Carbine Buffer Spring, Kaw Valley Precision 10oz 9mm Tungsten Buffer, Ballistic Advantage 16" 9mm Barrel, Spike's Stripped 9mm upper receiver, Spike's Tactical Battle Trigger, and MeanArms Magpul Pmag 9mm conversion. Recoil feels better than my sig 516 upper.
@@JustMe__ I know you asked him and hopefully he answers you, but I would suggest getting those charging handles that are meant to seal gasses from hitting your face. Most charging handles a kinda lose and they make some that seal the upper better.
@@JustMe__ Blowback is a little gassy due to the nature of its operation. A heavier buffer can help. Gas buster charging handles may help, but lose effectiveness during rapid fire strings.
Note when I say "100%", I mean it should feed, fire, and function as reliably as would be expected from a typical quality firearm. No mechanical system runs 100% perfectly 100% of the time. For simple blowback only, NOT for CMMG Banshee! More info: blowback9.wordpress.com/2022/08/18/4-step-guide-to-make-almost-any-ar9-run-100/
Correction, The only firearm that does this is a Glock. 25,000 rounds and have never had a malfunction of any kind. I clean mine after every range session. Alittle over the top but I take pride in all my firearms. My buddies at the range hate me because every time they have a problem they look up at me and I’m just firing away, enjoying life with no issues in my sidearm, your video is excellent. I remember when I first got into the AR9 and had to do the ole quarters trick. Mine runs like a machine now and have upgraded everything accordingly. I love my 5.56 but it’s so expensive. 9mm lets me practice AR controls at the range without spending that ridiculous amount that the 5.56 demands.
I went to the range for testing today. Using the adapter for colt magazines I found that it doesn't like a full 20rd magazine. Seems the bolt was binding up on initial charging. First ten round group ran great. Later on I was having ejection issues but I think it was because my mag adapter was loose. I appreciate all of your videos and hard work.
I’ve tried I don’t know how many magazine adapters, none work. Buy the Mean EndoMags. You have to have a 30 round PMag for them to work. Remove the internals and replace with the EndoMag internals. Flawless.
The only buffer that I could use for my FM-9 PCC was Mike 45 Heavy Buffer, designed for PCCs chambered for .45ACP rounds. Such a heavy buffer had solved all the problems that I had with my PCC, such as bolt bounce, FTFs and so on...
Just took my 9mm rifle for a test drive last week and it runs great. It’s an A5 system so I changed the bolt weight to compensate lighter A5H4 buffer. It runs great even with the Geissele rifle spring. It’s only 115gr factory ammo so hopefully it will work on heavier projectiles
Excellent content. This is the best part of youtube, when you learn valuable info. My ARV has been sitting in the safe because of problems that I think I can fix now. Thanks
Thanks for putting this together. I've been doing things wrong for to long. I some how was able to get a few reliable ar9's. But it wasnt easy. I had know Idea how simple the formula was. Now time to rebuild a couple of may favorites. Thank you. Subbed
Now if I could find someone who has the magic formula to load optimized 9mm carbine reloads. Looking for some 1600-1800 fps 65-90gr projectiles. Basically 9mm stingers.
Just earned yourself a subscriber by man. Ive had an extar ep9 for years that runs flawlessly until now. Apparently when you run an ar9 as fast as possible it runs into some issues. So this info is very helpful in diagnosing and correcting those issues in the goal of getting the most out of my ar9
My 1st AR 9 buiran flawlessly accept, as you stated. JHP tried modifying the feed cone and also tried installing a feed ramp it was a nogo. Installed a Taccom supper feed barrel problem solved . Great company great customer service
This dude's information has my PSA AR-V running like a champ. I use the 10oz KAK buffer and $1.75 in quarters in the tube to get my bolt within 1/4" of the bolt catch when pulled back, and it runs. I still plan to get a Macon barrel soon. Thanks!
OUTSTANDING GREAT information very clear to the point!!! good to know going into the 9mm AR, been doing Reg 556/300 and this has def opened my eyes to all the upcoming thank you for taking the time to explain
Great video, I actually read your articles online before seeing this video. I’ve definitely seen compelling evidence to support both sides of this topic. I plan on doing some testing with my FM9
I know this isn't the newest video but I wanted to say thanks for all of this info. after some preliminary firings on a new ar9 the amount of malfunctions were infuriating. after I watched your video I can say that now it runs flawlessly, regardless of how slow or fast I fire.
My AR9 is my favorite build so far and runs flawless Palmetto kit, Aero lower, 8oz buffer, was 4in barrel with kit swapped to 7in CBC ind barrel, law tac folder, Endo mag conversion
@@DubbinMoto nice I have all the right spring and buffer just can’t get it to cycle or feed properly after the first shot any idea what would make that problem
@@DubbinMotogot the feeding issues solved the real problem was the ejector is was to low and was not ejecting right the plastic part ejector had to move it up like u mention and solved the problem running ok now haven’t had many rounds but at its working some what !!!
I'll definitely second the heavier buffer. Had an out-of-battery discharge with a new build and not knowing about the buffer. I ordered an adjustable weight buffer and added the weights, now it runs like a dream.
Thanks for putting out this great information. I took your advice and bought the kak gold top buffer. While I was at it, I also bought their 9mm bolt. The bolt costs a little more than other bolts, but has a great feature that I haven’t seen elsewhere. The standard ar extractor has, instead of a roll pin, a partially threaded pin that allows you to easily remove the extractor for cleaning or replacement. I put both in my Colt 6450 and they work great, even fed a mag of hollow points.
Thank you for your dedication to this platform. Appreciate explaining for the people in the back row.lol but very helpful. I havent seen a video in your library that gets into your experience w/Stern Defence mag adapter . Ive built a few. But i value your input . Thank you sir.
Excellent video. Refreshing to finally see a youtuber that knows what the hell they're talking about talking about, and not a self proclaimed expert. I don't know your credentials, but you sir, are a "real" gunsmith.
Thank you for your video. I just bought an AR9 8" barrel. I haven't fired it yet. I check the buffer and its 3 quarter inch long same as what you shown. I think i will buy a new buffer 4" long before going to range .
Not a ton of rounds yet but my budget build has been 100% so far. My recipe: -Spinta barrel and upper receiver -FM 9mm bolt and buffer -Standard carbine spring -Standard Anderson lower receiver -Standard 556 mags with Endomag 9mm insert.
Three words regarding this video and Blowback9: TAKE HIS ADVICE. I'm a first time AR rifle builder and if not for these videos and the information on his website I would probably NOT have had the experience I did. I spent 4th of July 2024 assembling an AR 9 I had purchased in parts starting in March 2024. I followed the advice of Blowback9 regarding barrel choice, bolt carrier group, buffer weight, spring, and ejector tuning when I very carefully assembled my AR 9. I spent a good hour and a half tuning my ejector and it paid dividends I'm sure. My first trip to the range with my AR 9 : 1) My AR 9 Shot Fiocchi and Remington115 GR FMJ ammo flawlessly. 2) My AR 9 Shot Fiocchi 147 GR hollow points flawlessly. 3) My AR 9 Shot mixtures of FMJ and hollow points flawlessly. NO WAY could I have accomplished 1): 3) without watching the videos and visiting Blowback 9 Website. Thanks for the videos ! They are a God Send ! Kudos !
@@michaelshanahan4965 Iam having feeding issues with my by chance any idea what would be the issue i have right buffer and spring and BCG but can get around the feeding problem
Something wrong with my FX-9. Pull trigger and get a click. Was working perfectly last week. Disassembled to clean, including trigger, and now it’s not firing. Dry fire works fine. Getting a faint primer strike. I thought firing pin might be stuck but you can push it through from the back manually. Took it out and cleaned it and the spring. Still no bang. Thoughts?
Thanks again. Yup, my homebuild ejector was out of alignment, and rounded (PSA, dedicated Colt mag lower). Went ahead and bent it into alignment. and filed the face of it flat and as square as I can get it. It is in much better alignment with the ejector channel/bolt face now. My Saint Victor 9mm ejector, was already in very good alignment with the ejector channel, but the tip was rounded, so I filed it flat/square, as best I could. Tidbit about the Saint Victor, it uses a plastic/rubber spacer at the butt end of the buffer spring, with a 3.25" buffer, of unknown weight. It is relatively light recoiling, for that lower mass combo. Wish I knew what spring they use. It doesn't take much force to pull the BCG back. I'd say it takes signifigantly less force to open then my 11oz buffered, flat wire buffer sprung, KVP bolt, home build.
That rubber spacer is similar to what Colt did so they could keep using carbine-length buffers - they stuck a 3/4" spacer in the back of the spring to make up the length difference and to stop breaking bolt catches.
@@Blowback9question, I got an ar9 and the guy before was using the ole quarter trick in the carbine buffer tube. I want to get away from that and turn the machine legit. Will buying the 4 inch buffer do the job or will I also have to buy the spacer in conjunction with the 4 inch buffer weight? Thanks
big stuff right here thanks! been screwing with mine few years now but I love it. trying to get them short is a problem for me put the Dead foot arms 2.5" brace on and it went nuts on me. changed the trigger stopped the full auto, got a "guaranteed to feed" barrel only feeds flat tips when I add a little oil to the cone although I noticed after the cone dried up it kept running them. so may just need a wear in. I do have a stove pipe or a spent casing left in the chamber causing misfeeds so I did notice the ejector was not snug as your pic. It took me a few times but it looks a little more snug. will try this out at the range tomorrow. I bent a little too much and was hitting one of my dummy rounds causing it to nose up and jam. took a little off seems to be better now. dead foot arms has their "modified cycle system" which is a spring within a spring setup. diff weight springs to play with. I have since stuck with 165gr subs I load myself as they are gentle on the gun and it runs. I stay away from supers just because it seems so ruff on the entire gun. stuff was coming loose at one point the upper pin housing actually broke and angstadt sent me a new one. so running supers with the DFA is a no for me. I might have the spring setup good now and with the trigger correct maybe I can try again but for now it's cushy subs. I run a can and that seemed to magnify the issues as well. thanks for the vid! liked n subscribed sir.
My epc9 is a frankenrifle. Sprinco buffer spring for carbine, Aero buffer like you tossed. Foxtrot Mike's bolt, NBS BARREL and LaRue trigger. Larue trigger best ever. No mim used. My first 9mm runs like mad. On magpul mags. Kingslayer with green dot and ring. Odinworks handguard.
OK, I was having a problem with a Glock 33 round magazine loaded with Berry's 124 gr hp bullets. The bullet would just jam into the bottom edge of the barrel chamber. I replaced the barrel with a Ballistic Advantage 8.3" EPC 9MM barrel. I polished the face for good measure. It now feeds the Berry bullets with no problem. I did notice a little dent on the edge of the bullet but they are softer than jacketed bullets. I am a happy boy. Thanks!
Bro just use FMJ rounds. The tips on HP don’t like feeding ramps much. Besides, why use HPs? More expensive, not reliable at feeding correctly, can’t penetrate cars or body armor. They want you to use HP so you can’t pierce their body armor or vehicles as well. Speaking of ATF agents btw. They are your biggest threat.
The FX9 bolt is only 12.8 ounces. I am using the Lockhart Tactical extended (4-inch) and tunable (adjustable weight) buffer at a weight of 9.8 ounces. So combined weight is 22.6 ounces.
This is the way. My Aero EPC9 is now running like a scalded ape without a single issue since ditching the (Aero BCG) for a proper one with the feed lug and 5.56 extractor.
Boy howdy, did I miss out on a lot of headaches by getting a YHM upper with all these issues worked out for me. I do think I need to step back and start from scratch by weighing my bolt and buffer.
Built my own a couple years ago doing my own research Arv builders kit Macon Deadblow buffer 8" Macon barrel Franklin armory binary trigger andspring Feels like a machine gun
Thank you for taking the time to put out this information! New to the blowback AR9 world and have recently purchased a Bear Creek Arsenal side charge blowback upper with 16" barrel. Do the same rules apply for the buffer and buffer spring when using a full length buffer tube? First range trip using the provided buffer & standard AR buffer spring. The side charging handle and was broken off within the first 20 rounds. Just wonder if there's something I'm overlooking.
Just installed the Wilson Combat flat wire carbine spring in all by ARs 9mm & 5.56. They all had the twang before and it is gone after I installed the springs.
First time watching your channel very informative thank you very much keep up the great work. Bought a psa AV9 that throws the empty brass 25 feet at the 1, Oclock position and bottms out the bolt very violently. Thans for the tips
Excellent content sir. Much needed information for the frustrated masses. Have you found the feed ramp that is used by Taccom in their barrels to be beneficial? Overkill?
I saw a kit for a colt 9mm smg the other day. Its a colt 9 mm smg that jus has a little square cut out of the lower where the hammer and trigger pins go, and a square cut out where the auto sear pin hole was.
I just bought a Foxtrot Mike lower and a PSA 8" upper. I got a 7.5 oz Macon Armory dead blow buffer and standard carbine spring. I've shot about 100 rounds including 115gr fmj, 147 gr fmj and HST 147 gr HP. It has run flawlessly so far. I noted the buffer + bolt is just under 22 oz and the ejector is slightly away from the bolt and down some in the ejector groove. There is copper rub marks on the chamber face of the barrel. I am thinking if it ain't broke don't fix it but it would also be very easy to install a Ballistic Advantage barrel, just in case. I also have a YHM R9 suppressor waiting on a tax stamp. I wonder if I should get a heavier buffer. Flat wire buffer spring is on the way.
Yes, if it ain't broke, don't fix it! Just be aware that if you have ejection problems the ejector may need tweaking. If the total mass is near 22oz, it should be fine!
I have a FM lower and a PSA 16" upper. I switched to a used carbine spring and an 8.3oz sliding-weight buffer for a total weight of 22.5oz. After making that change and testing it with a box of ammo, we took it to Steel Challenge where my wife and I averaged about 175 rounds each without a hiccup using Blazer brass 115gr. I also noticed that the ejector is sitting a little low, but it extracts fine. (Well, there are some brass marks on the upper part of the ejection port.) I wonder how easy it is to adjust. The only problem we had before was with loading new 33-round magazines too full. (28 to 30 rounds seems to work.) Ammo would get smashed into the lower part of the chamber face or whatever it's called. The odd thing is that it seemed to need to be loaded even less with 124gr and even less with 147gr. I'm guess ammo mass had something to do with that, and I wonder if the fast moving bolt was part of the reason in addition to the stiff springs in the magazines. The reciprocating mass was 20.6oz with a .308 spring, so the bolt was flying home in a hurry!
Great video!!! I bought a Macon Armory "deadblow" buffer, Wilson Combat flatwire carbine spring, and a Cryptic Coating bolt. Total weight is 21 oz. Is that 1 ounce going to present any trouble?
My AR9 functioned perfectly for me after getting the heavy buffer and I added a piece of Delrin in the buffer tube to prevent the bolt from over-traveling on recoil. BUT I had a bullet Glock mag lower in my AR9 for the forst 3000 or so rounds. I changed over to a standard AR lower and tried out the Mean Arms 9mm mag conversions and the follow up shot jams straight into the bottom of the barrel, pushing the bullet inside of the case, ruining the round. I'm going to guess that I need a feed ramp. My barrel's feed cone looks to be less than that Colt style feed cone. It looks more like my KelTec Sub2000 feed cone. This feed cone works well with the Glock mags because the Glock mags hold the bullet closer to the chamber and the angle is better in the Glock mag than with the Mean Arms mag conversions. I assume the back of the 9mm case is unsupported when there is the larger feed cone? Is that the true? If it works, that's fine by me. I was thinking of just using a Dremel to add a feed ramp to the bottom of my barrel and try that. If that doesnt' fix it, I can chuck the barrel in my lathe and enlarge the feed cone.
The cartridge base will have a little less support with a larger feed cone, but I've never had a problem and haven't seen any problems reported with brass ammo.
@@Blowback9 That's good to know. I bought some stainless steel 1/8" drill rod to make an indexing pin for my barrel. I drilled the barrel for the pin and installed it, so the barrel can't spin now. I'm going to try to just Dremel a feed ramp into the bottom of the barrel & see if that works. If not, I can always enlarge the feed cone on the lathe. This is my first AR9 so maybe there is a reason for the barrel to be extremely thick and heavy? I milled in a couple of flats on the barrel so I can get a wrench on it for taking the muzzle device on and off without damaging the aluminum receiver now that it has an index pin. I was thinking maybe I can turn the barrel down some to lighten it up a bit. As much as I like my AR9, it's a very heavy gun for what it is.
I was wondering if you have any recommendations on my setup, I have a EPC9 with the EPC 8” barrel running a Spectre9 suppressor, What do you recommend for a buffer weight and spring setup. Thank you for any information
Good information. This vid helped me remedy a ejection issue. Question for you and all. I have a custom made by me a 12 ounce buffers both have 4 tungsten weights One the weight's do not reciprocate basically solid the other the weights move a little ie .055 of movement. I've not tested them yet but what's your advice on solid or reciprocating? Also if you suggest reciprocating weights is .055 enough reciprocating clearance?
IIRC, milspec carbine buffers use about .125" recip. clearance internally. KAK 9mm buffers use a lot less and they seem to be effective in my slow motion vids, so .05 may be OK. I always use buffers with reciprocating weights to help prevent bolt bounce and OOB burst cartridges during rapid fire.
@@Blowback9okay. So reciprocating weight is more effective at controlling bolt bounce? Ooh I also forgot to mention I'm not using any rubber spacer at all. Appreciate the information too.
I have a Christensen arms CA9mm and it has failures to feed and idk if it’s the barrel or if it’s having bolt bounce but I know it could be both it has shot halfway out of battery before
Failure to feed problems could also cause bullet setback resulting in overpressure and premature extraction. It would look like an OOB. An enhanced feed cone and sliding weights buffer are almost always good choices.
This sounds like more than just a FP spring problem. Send me an email or chat on Reddit if you would like help diagnosing. Contact info on my site: blowback9.com
The same principles should apply for the spring, feeding, and ejection. The total mass probably needs to be higher for a .40, but I don't know what it should be.
Can you have a buffer that is too heavy? Would a system too heavy cause the bolt not to cycle far enough to feed another round? Does having a heavy buffer delay the opening of the bolt/chamber to allow for more muzzle velocity?
Probably not. However, I'd put it together and test it before doing anything. If it has problems feeding the ammo you choose, then it may be necessary to look into barrels with enhanced feed cones.
Man glad I found your video I am having problems with double fires and have replaced the trigger group. It’s a bear creek and I know you get what you pay for lol but it does have a regular buffer that it came with. Would you have any other suggestions or things to try?
@@Blowback9 ok the one I ordered was I believe 8.3 with a flat carbine spring I also order the Wilson combat spring. I do not have a way to way them at the moment. Thank you for the response
But, I do have a question with all this information great information how will the result be with a suppress system? Because that will be the main goal have it.
Do you have a video on Rifle Length Buffers? Because I cant find a 9mm buffer made for a Rifle length buffer tube. I have a CTS Aktive buffer currently in my rifle. It weight 6.5 oz. I should be receiving my PSA Gen 4 9mm upper in a couple days. So I am hoping it works.
Im using a standard 556 lower..so i bought the sylvan arms magwell adapter and that has its own ejector that seems to be short..doesnt reach the top of the channel of the bcg. Is there a magwell adapter you can recommend that would work better and accept glock mags?
Doug, do you know any solutions for an ejector using a 5.56 lower without using the mag well insert kit? I know the Endo mags act as the ejector, but I like the fact the mag has to be in to eject a round.
@@Blowback9 thanks. With some research, I think the cmmg bolt would work too since it would have an ejector. But I would have to get their barrel also.
I have been a frustrated owner of a 9mm AR for years! It took a lot of time and research to get my 9mm AR running reliably. I am glad to see that you are putting all the important information in one place for future 9mm AR owners to find easily. I wish your page existed ten years ago.
I haven’t watched this video yet, but judging by this dudes work bench and 5 seconds of his voice, I am 100% confident he knows exactly what he’s talking about.
Damn. I’ve been chasing my ejection issues the past two range sessions. My ejector was a point and at the bottom of the bolt. Squared it off, moved up and in and never ejected better. Thank you sir.
I was having ejector issues with my AR-9, it was low but I recently adjusted it to how you showed. Haven’t got to test it out yet. Great video and information
I swear now that I've figured the feed ramp out after finding a single video with very specific and extensive key word searches on multiple apps, youtube has decided I'm allowed to see the pantheon of videos that I looked for initially many moons ago. You're doing the community a great service sir. Sorry for being years late to the party, i was caught in algorithm traffic.
Helpful info. I got lucky!!! I purchased a built Foxtrot Mike AR9 upper and then their factory built lower separately. I put the 2 together and it’s been 100% reliable from day 1. After adding a suppressor, all I had to do is add a heavier buffer. (45ACP) 7.50oz
Going to hit the range today!!!
Enjoyed the vid.
Good to hear! Have fun, be safe!
I’ve reviewed your website in addition to watching your videos. I think I’ll get a Kynshot hydraulic buffer. V’s the KAK.
What’s better….. RB5000HP with 2 extra weights or the RB5015HD with 1 extra weight? For now I will assume it’s the RB5000HP because it adds up to more total mass. Thanks.
You're right, the 5000HP + 2 has better felt recoil. For the correct 9mm bolt travel, they need to be paired with an A5 length buffer tube (7.75" internal). @@scott2228
This is the rout I’ll go. I can’t go longer than A5 bc the gun would no longer fit in it’s dedicated range bag. Lol. A5 will b right. Thanks for all ur help.
I really appreciate all of your research! I was able to build my 9mm AR upper with 100% function and reliability first try with your info and reply's. Here is my build for anyone wondering: BKings Bolt Carrier Group, BKings Carbine Buffer Spring, Kaw Valley Precision 10oz 9mm Tungsten Buffer, Ballistic Advantage 16" 9mm Barrel, Spike's Stripped 9mm upper receiver, Spike's Tactical Battle Trigger, and MeanArms Magpul Pmag 9mm conversion. Recoil feels better than my sig 516 upper.
I rarely comment on youtube content but this is great info and well presented. I’ve learned so much from this video alone.
Thank you for what you do.
Ahhh, that feeling when you find the exact youtube channel you were looking for = Bliss 😁
Great video! Wish your video was around when I built my AR9s. I had to learn all this on my own. Good job!
I was LITERALLY about to ask if you were the guy who runs that awesome site full of great info and you answered it on your first sentence. Subscribed.
That's me! Thanks!
@Blowback9 what can you do to make a 9mm ar v stop having some much gas blowback in your face
@@JustMe__ I know you asked him and hopefully he answers you, but I would suggest getting those charging handles that are meant to seal gasses from hitting your face. Most charging handles a kinda lose and they make some that seal the upper better.
@@JustMe__ Blowback is a little gassy due to the nature of its operation. A heavier buffer can help. Gas buster charging handles may help, but lose effectiveness during rapid fire strings.
Note when I say "100%", I mean it should feed, fire, and function as reliably as would be expected from a typical quality firearm. No mechanical system runs 100% perfectly 100% of the time. For simple blowback only, NOT for CMMG Banshee! More info: blowback9.wordpress.com/2022/08/18/4-step-guide-to-make-almost-any-ar9-run-100/
What about a good old Glock
Correction, The only firearm that does this is a Glock. 25,000 rounds and have never had a malfunction of any kind. I clean mine after every range session. Alittle over the top but I take pride in all my firearms. My buddies at the range hate me because every time they have a problem they look up at me and I’m just firing away, enjoying life with no issues in my sidearm, your video is excellent. I remember when I first got into the AR9 and had to do the ole quarters trick. Mine runs like a machine now and have upgraded everything accordingly. I love my 5.56 but it’s so expensive. 9mm lets me practice AR controls at the range without spending that ridiculous amount that the 5.56 demands.
I’m guessing we should all give up on the CMMG Banshee? I’m only seeing negative reviews about this gun. Any input??
I went to the range for testing today. Using the adapter for colt magazines I found that it doesn't like a full 20rd magazine. Seems the bolt was binding up on initial charging. First ten round group ran great. Later on I was having ejection issues but I think it was because my mag adapter was loose. I appreciate all of your videos and hard work.
I’ve tried I don’t know how many magazine adapters, none work. Buy the Mean EndoMags. You have to have a 30 round PMag for them to work. Remove the internals and replace with the EndoMag internals. Flawless.
The only buffer that I could use for my FM-9 PCC was Mike 45 Heavy Buffer, designed for PCCs chambered for .45ACP rounds. Such a heavy buffer had solved all the problems that I had with my PCC, such as bolt bounce, FTFs and so on...
Very clear and concise information. This is the best short video on this topic I have been able to find. Thanks!
Just took my 9mm rifle for a test drive last week and it runs great. It’s an A5 system so I changed the bolt weight to compensate lighter A5H4 buffer. It runs great even with the Geissele rifle spring. It’s only 115gr factory ammo so hopefully it will work on heavier projectiles
I just put my 1st 9mm together, and it would NOT shoot. I watched this video and did what you said. The thing works like a top now! Thanks
Excellent content. This is the best part of youtube, when you learn valuable info. My ARV has been sitting in the safe because of problems that I think I can fix now. Thanks
Swap out the charging handle the one on my arv was out of spec it runs perfect now
Thanks for putting this together. I've been doing things wrong for to long. I some how was able to get a few reliable ar9's. But it wasnt easy. I had know Idea how simple the formula was. Now time to rebuild a couple of may favorites. Thank you. Subbed
Now if I could find someone who has the magic formula to load optimized 9mm carbine reloads. Looking for some 1600-1800 fps 65-90gr projectiles. Basically 9mm stingers.
@@JAM4MOREI think you would have to be weary of throat erosion with those kinds of loadings.
Just earned yourself a subscriber by man. Ive had an extar ep9 for years that runs flawlessly until now. Apparently when you run an ar9 as fast as possible it runs into some issues. So this info is very helpful in diagnosing and correcting those issues in the goal of getting the most out of my ar9
My 1st AR 9 buiran flawlessly accept, as you stated. JHP tried modifying the feed cone and also tried installing a feed ramp it was a nogo. Installed a Taccom supper feed barrel problem solved . Great company great customer service
One of the best resources out here! My build is running substantially better. Thanks!
very good video. thanks for including picture of ejector alignment.
Glad you liked it!
VERY interesting.
This blows a hole in the use of the CMMG Conversion kits. I was considering buying one but now I am very apprehensive.
Thanks!
Very informative, thank you. I haven't finished my build yet due to all of these problems that I've heard about.
This dude's information has my PSA AR-V running like a champ. I use the 10oz KAK buffer and $1.75 in quarters in the tube to get my bolt within 1/4" of the bolt catch when pulled back, and it runs. I still plan to get a Macon barrel soon. Thanks!
Great to hear!
OUTSTANDING GREAT information very clear to the point!!! good to know going into the 9mm AR, been doing Reg 556/300 and this has def opened my eyes to all the upcoming thank you for taking the time to explain
Great video, I actually read your articles online before seeing this video. I’ve definitely seen compelling evidence to support both sides of this topic. I plan on doing some testing with my FM9
I know this isn't the newest video but I wanted to say thanks for all of this info. after some preliminary firings on a new ar9 the amount of malfunctions were infuriating. after I watched your video I can say that now it runs flawlessly, regardless of how slow or fast I fire.
My AR9 is my favorite build so far and runs flawless
Palmetto kit, Aero lower, 8oz buffer, was 4in barrel with kit swapped to 7in CBC ind barrel, law tac folder, Endo mag conversion
How is it running Iam having trouble with my endomag I think it’s feeding issues?
@@MrTuna714 haven't had any notable issues. I'm am swapping to a different buffer soon because I am getting a little bit of bolt bounce
@@DubbinMoto nice I have all the right spring and buffer just can’t get it to cycle or feed properly after the first shot any idea what would make that problem
@@MrTuna714 I have ideas but would need some pictures of your build. We should move this to DMs
@@DubbinMotogot the feeding issues solved the real problem was the ejector is was to low and was not ejecting right the plastic part ejector had to move it up like u mention and solved the problem running ok now haven’t had many rounds but at its working some what !!!
I'll definitely second the heavier buffer. Had an out-of-battery discharge with a new build and not knowing about the buffer. I ordered an adjustable weight buffer and added the weights, now it runs like a dream.
Nice!
Great video I’ve done everything you said but I had to learn the hard way. Found your video a year later.
Thanks for putting out this great information. I took your advice and bought the kak gold top buffer. While I was at it, I also bought their 9mm bolt. The bolt costs a little more than other bolts, but has a great feature that I haven’t seen elsewhere. The standard ar extractor has, instead of a roll pin, a partially threaded pin that allows you to easily remove the extractor for cleaning or replacement. I put both in my Colt 6450 and they work great, even fed a mag of hollow points.
Thank you for the barrel info, will be getting mine fixed asap
Thank you for your dedication to this platform. Appreciate explaining for the people in the back row.lol but very helpful. I havent seen a video in your library that gets into your experience w/Stern Defence mag adapter . Ive built a few. But i value your input . Thank you sir.
Excellent video. Refreshing to finally see a youtuber that knows what the hell they're talking about talking about, and not a self proclaimed expert. I don't know your credentials, but you sir, are a "real" gunsmith.
Just had my first one doing some quick drills. It looks like my issue is now upgrading the spring and trying to find sliding buffer weight
Great video
will try this with mine, thank you.
Good stuff as usual, happy to be a subscriber. Going to have a look a the ejectors on mine now. Can't really remedy the feed cones.
Thank you for your video. I just bought an AR9 8" barrel. I haven't fired it yet. I check the buffer and its 3 quarter inch long same as what you shown. I think i will buy a new buffer 4" long before going to range .
Not a ton of rounds yet but my budget build has been 100% so far.
My recipe:
-Spinta barrel and upper receiver
-FM 9mm bolt and buffer
-Standard carbine spring
-Standard Anderson lower receiver
-Standard 556 mags with Endomag 9mm insert.
How is it running I have same endo mag but having feeding issues
@@MrTuna714
No issues yet but only about a couple of hundred rounds so far.
One day I’ll get a dedicated lower for it.
Three words regarding this video and Blowback9:
TAKE HIS ADVICE.
I'm a first time AR rifle builder and if not for these videos and the information on his website I would probably NOT
have had the experience I did.
I spent 4th of July 2024 assembling an AR 9 I had purchased in parts starting in March 2024. I followed the advice
of Blowback9 regarding barrel choice, bolt carrier group, buffer weight, spring, and ejector tuning when I very carefully assembled my AR 9. I spent a good hour and a half tuning my ejector and it paid dividends I'm sure.
My first trip to the range with my AR 9 :
1) My AR 9 Shot Fiocchi and Remington115 GR FMJ ammo flawlessly.
2) My AR 9 Shot Fiocchi 147 GR hollow points flawlessly.
3) My AR 9 Shot mixtures of FMJ and hollow points flawlessly.
NO WAY could I have accomplished 1): 3) without watching the videos and visiting Blowback 9 Website.
Thanks for the videos ! They are a God Send ! Kudos !
Another tip for spring noise is some plane old grease on the recoil spring. This works with any caliber AR-15.
True! Messy, but it works!
I use Mean Arms EndoMags, ejector is part of magazine.
Me too are u having any issues
@@MrTuna714 Absolutely none, my son and I have 12 of these between us with thousands of rounds fired. No wear ejectors look brand new.
@@michaelshanahan4965 Iam having feeding issues with my by chance any idea what would be the issue i have right buffer and spring and BCG but can get around the feeding problem
Something wrong with my FX-9.
Pull trigger and get a click.
Was working perfectly last week.
Disassembled to clean, including trigger, and now it’s not firing.
Dry fire works fine.
Getting a faint primer strike.
I thought firing pin might be stuck but you can push it through from the back manually. Took it out and cleaned it and the spring. Still no bang.
Thoughts?
Feeding, ejection and last bolt hold seems to be it
Thanks again.
Yup, my homebuild ejector was out of alignment, and rounded (PSA, dedicated Colt mag lower). Went ahead and bent it into alignment. and filed the face of it flat and as square as I can get it. It is in much better alignment with the ejector channel/bolt face now.
My Saint Victor 9mm ejector, was already in very good alignment with the ejector channel, but the tip was rounded, so I filed it flat/square, as best I could.
Tidbit about the Saint Victor, it uses a plastic/rubber spacer at the butt end of the buffer spring, with a 3.25" buffer, of unknown weight. It is relatively light recoiling, for that lower mass combo. Wish I knew what spring they use. It doesn't take much force to pull the BCG back. I'd say it takes signifigantly less force to open then my 11oz buffered, flat wire buffer sprung, KVP bolt, home build.
That rubber spacer is similar to what Colt did so they could keep using carbine-length buffers - they stuck a 3/4" spacer in the back of the spring to make up the length difference and to stop breaking bolt catches.
@@Blowback9question, I got an ar9 and the guy before was using the ole quarter trick in the carbine buffer tube. I want to get away from that and turn the machine legit. Will buying the 4 inch buffer do the job or will I also have to buy the spacer in conjunction with the 4 inch buffer weight? Thanks
@@DIXONSIDER00 With a 4" buffer the extra spacer in the back of the buffer spring is not necessary when using a carbine buffer tube.
@@Blowback9 do you have any experience with the spikes tactical st-9x 9mm heavy buffer?
@@Blowback9 it’s 7.7 oz
big stuff right here thanks! been screwing with mine few years now but I love it. trying to get them short is a problem for me put the Dead foot arms 2.5" brace on and it went nuts on me. changed the trigger stopped the full auto, got a "guaranteed to feed" barrel only feeds flat tips when I add a little oil to the cone although I noticed after the cone dried up it kept running them. so may just need a wear in. I do have a stove pipe or a spent casing left in the chamber causing misfeeds so I did notice the ejector was not snug as your pic. It took me a few times but it looks a little more snug. will try this out at the range tomorrow. I bent a little too much and was hitting one of my dummy rounds causing it to nose up and jam. took a little off seems to be better now. dead foot arms has their "modified cycle system" which is a spring within a spring setup. diff weight springs to play with. I have since stuck with 165gr subs I load myself as they are gentle on the gun and it runs. I stay away from supers just because it seems so ruff on the entire gun. stuff was coming loose at one point the upper pin housing actually broke and angstadt sent me a new one. so running supers with the DFA is a no for me. I might have the spring setup good now and with the trigger correct maybe I can try again but for now it's cushy subs. I run a can and that seemed to magnify the issues as well. thanks for the vid! liked n subscribed sir.
Thanks! Did the ejector adjustment help?
ran perfectly! I mentioned you in my vid published yesterday and put a link to your channel in my description. thanks a lot! @@Blowback9
You bet - thank you!@@magdumpmonday
My epc9 is a frankenrifle.
Sprinco buffer spring for carbine, Aero buffer like you tossed. Foxtrot Mike's bolt, NBS BARREL and LaRue trigger. Larue trigger best ever. No mim used. My first 9mm runs like mad. On magpul mags. Kingslayer with green dot and ring. Odinworks handguard.
OK, I was having a problem with a Glock 33 round magazine loaded with Berry's 124 gr hp bullets. The bullet would just jam into the bottom edge of the barrel chamber. I replaced the barrel with a Ballistic Advantage 8.3" EPC 9MM barrel. I polished the face for good measure. It now feeds the Berry bullets with no problem. I did notice a little dent on the edge of the bullet but they are softer than jacketed bullets. I am a happy boy. Thanks!
Bro just use FMJ rounds. The tips on HP don’t like feeding ramps much. Besides, why use HPs? More expensive, not reliable at feeding correctly, can’t penetrate cars or body armor. They want you to use HP so you can’t pierce their body armor or vehicles as well. Speaking of ATF agents btw. They are your biggest threat.
Going to Subscribe now for future use after I get my AR9! lol
Thanks!
The FX9 bolt is only 12.8 ounces. I am using the Lockhart Tactical extended (4-inch) and tunable (adjustable weight) buffer at a weight of 9.8 ounces. So combined weight is 22.6 ounces.
That bolt is super light. Many bolts weigh 12oz. if the rear weight is missing. Is the rear bolt weight missing?
This is the way. My Aero EPC9 is now running like a scalded ape without a single issue since ditching the (Aero BCG) for a proper one with the feed lug and 5.56 extractor.
Boy howdy, did I miss out on a lot of headaches by getting a YHM upper with all these issues worked out for me. I do think I need to step back and start from scratch by weighing my bolt and buffer.
Brownells also has the correct PCC buffer.
I bought 5-k of wolf long ago .
Never a issue feeding
I like to use an Odin works barrel, tool craft bcg, with armaspec buffer. Great combo runs flawlessly with the mean arms magazine conversion.
Odin works has a great adjustable buffer for AR9s as well
Built my own a couple years ago doing my own research
Arv builders kit
Macon Deadblow buffer
8" Macon barrel
Franklin armory binary trigger andspring
Feels like a machine gun
Very informative.... Thank you
Thx
My FM9 does not reliably feed hollow points. In the process now of finding a new barrel. Thanks for the info!
How about the blowback 9 mm from Springfield Armory with the colt mags?
Not may reports out yet. Time will tell!
Thank you for taking the time to put out this information!
New to the blowback AR9 world and have recently purchased a Bear Creek Arsenal side charge blowback upper with 16" barrel. Do the same rules apply for the buffer and buffer spring when using a full length buffer tube?
First range trip using the provided buffer & standard AR buffer spring. The side charging handle and was broken off within the first 20 rounds. Just wonder if there's something I'm overlooking.
Not familiar with that upper, but the same rules should apply. I'd need more details - send me an email.
@@Blowback9 Will do, thanks Doug.
Just installed the Wilson Combat flat wire carbine spring in all by ARs 9mm & 5.56. They all had the twang before and it is gone after I installed the springs.
Must use 9MM 10 to 11 oz PCC buffer. (PSA 9MM complete upper). Along with flat wire buffer spring and the Mean Arms EndoMags.
Thanks for what you are doing!
First time watching your channel very informative thank you very much keep up the great work. Bought a psa AV9 that throws the empty brass 25 feet at the 1, Oclock position and bottms out the bolt very violently. Thans for the tips
Thank you for the knowledgeable video
Thanks for the info!
Excellent content sir. Much needed information for the frustrated masses. Have you found the feed ramp that is used by Taccom in their barrels to be beneficial? Overkill?
I haven't played with Taccom barrels, but all reports are that their barrel feed ramps work well.
I saw a kit for a colt 9mm smg the other day. Its a colt 9 mm smg that jus has a little square cut out of the lower where the hammer and trigger pins go, and a square cut out where the auto sear pin hole was.
I just bought a Foxtrot Mike lower and a PSA 8" upper. I got a 7.5 oz Macon Armory dead blow buffer and standard carbine spring. I've shot about 100 rounds including 115gr fmj, 147 gr fmj and HST 147 gr HP. It has run flawlessly so far. I noted the buffer + bolt is just under 22 oz and the ejector is slightly away from the bolt and down some in the ejector groove. There is copper rub marks on the chamber face of the barrel. I am thinking if it ain't broke don't fix it but it would also be very easy to install a Ballistic Advantage barrel, just in case. I also have a YHM R9 suppressor waiting on a tax stamp. I wonder if I should get a heavier buffer. Flat wire buffer spring is on the way.
Yes, if it ain't broke, don't fix it! Just be aware that if you have ejection problems the ejector may need tweaking. If the total mass is near 22oz, it should be fine!
I ordered the Ballistic Advantage EPC 8.3" barrel. I replaced the PSA forend with a Dirty bird 7" one so I know how easy it is to change the barrel.
I have a FM lower and a PSA 16" upper. I switched to a used carbine spring and an 8.3oz sliding-weight buffer for a total weight of 22.5oz. After making that change and testing it with a box of ammo, we took it to Steel Challenge where my wife and I averaged about 175 rounds each without a hiccup using Blazer brass 115gr. I also noticed that the ejector is sitting a little low, but it extracts fine. (Well, there are some brass marks on the upper part of the ejection port.) I wonder how easy it is to adjust.
The only problem we had before was with loading new 33-round magazines too full. (28 to 30 rounds seems to work.) Ammo would get smashed into the lower part of the chamber face or whatever it's called. The odd thing is that it seemed to need to be loaded even less with 124gr and even less with 147gr. I'm guess ammo mass had something to do with that, and I wonder if the fast moving bolt was part of the reason in addition to the stiff springs in the magazines. The reciprocating mass was 20.6oz with a .308 spring, so the bolt was flying home in a hurry!
Pretty much set up I’m working on, the lower pair up with the PSA ok? Is it running better with the barrel upgrade, any new rub marks? Thanks!
Great video!!! I bought a Macon Armory "deadblow" buffer, Wilson Combat flatwire carbine spring, and a Cryptic Coating bolt. Total weight is 21 oz. Is that 1 ounce going to present any trouble?
Great information man
Thank you
Welcome!
What company do suggest for buffers and such
Very good video! 💯👍
Draco 9s smooth af
AR9 jumps around like a hip hop concert
Check the "Gentle Recoil System" video/pages. It really calms down the AR9.
My AR9 functioned perfectly for me after getting the heavy buffer and I added a piece of Delrin in the buffer tube to prevent the bolt from over-traveling on recoil. BUT I had a bullet Glock mag lower in my AR9 for the forst 3000 or so rounds. I changed over to a standard AR lower and tried out the Mean Arms 9mm mag conversions and the follow up shot jams straight into the bottom of the barrel, pushing the bullet inside of the case, ruining the round. I'm going to guess that I need a feed ramp. My barrel's feed cone looks to be less than that Colt style feed cone. It looks more like my KelTec Sub2000 feed cone. This feed cone works well with the Glock mags because the Glock mags hold the bullet closer to the chamber and the angle is better in the Glock mag than with the Mean Arms mag conversions.
I assume the back of the 9mm case is unsupported when there is the larger feed cone? Is that the true? If it works, that's fine by me. I was thinking of just using a Dremel to add a feed ramp to the bottom of my barrel and try that. If that doesnt' fix it, I can chuck the barrel in my lathe and enlarge the feed cone.
The cartridge base will have a little less support with a larger feed cone, but I've never had a problem and haven't seen any problems reported with brass ammo.
@@Blowback9 That's good to know. I bought some stainless steel 1/8" drill rod to make an indexing pin for my barrel. I drilled the barrel for the pin and installed it, so the barrel can't spin now. I'm going to try to just Dremel a feed ramp into the bottom of the barrel & see if that works. If not, I can always enlarge the feed cone on the lathe.
This is my first AR9 so maybe there is a reason for the barrel to be extremely thick and heavy? I milled in a couple of flats on the barrel so I can get a wrench on it for taking the muzzle device on and off without damaging the aluminum receiver now that it has an index pin. I was thinking maybe I can turn the barrel down some to lighten it up a bit. As much as I like my AR9, it's a very heavy gun for what it is.
I can’t seem to find a ar15 flat wire carbine spring on Wilson combat. Only ar10
Thank you for this.
Great info, thank you
Great presentation. Thank you Sir.
I was wondering if you have any recommendations on my setup, I have a EPC9 with the EPC 8” barrel running a Spectre9 suppressor, What do you recommend for a buffer weight and spring setup. Thank you for any information
Good information. This vid helped me remedy a ejection issue.
Question for you and all.
I have a custom made by me a 12 ounce buffers both have 4 tungsten weights
One the weight's do not reciprocate basically solid the other the weights move a little ie .055 of movement. I've not tested them yet but what's your advice on solid or reciprocating?
Also if you suggest reciprocating weights is .055 enough reciprocating clearance?
IIRC, milspec carbine buffers use about .125" recip. clearance internally. KAK 9mm buffers use a lot less and they seem to be effective in my slow motion vids, so .05 may be OK. I always use buffers with reciprocating weights to help prevent bolt bounce and OOB burst cartridges during rapid fire.
@@Blowback9okay. So reciprocating weight is more effective at controlling bolt bounce?
Ooh I also forgot to mention I'm not using any rubber spacer at all. Appreciate the information too.
I have a Christensen arms CA9mm and it has failures to feed and idk if it’s the barrel or if it’s having bolt bounce but I know it could be both it has shot halfway out of battery before
Failure to feed problems could also cause bullet setback resulting in overpressure and premature extraction. It would look like an OOB. An enhanced feed cone and sliding weights buffer are almost always good choices.
@@Blowback9 The Christensen has powder weights in it and is not a cheap one so I’m thinking it’s the feed cone
Ive had issues with firing pin springs all being different and causing ftf when to heavy on ar9's. Even had the bolt maker send new lighter springs
This sounds like more than just a FP spring problem. Send me an email or chat on Reddit if you would like help diagnosing. Contact info on my site: blowback9.com
@Blowback9 problem was fixed last year with a different spring. The cause is lack of a shared spec from oem's on what parts to use
Does any of this apply to my ar40?
The same principles should apply for the spring, feeding, and ejection. The total mass probably needs to be higher for a .40, but I don't know what it should be.
Can you have a buffer that is too heavy? Would a system too heavy cause the bolt not to cycle far enough to feed another round? Does having a heavy buffer delay the opening of the bolt/chamber to allow for more muzzle velocity?
Try here: blowback9.wordpress.com/2022/09/30/the-overmass-project-worlds-heaviest-9mm-blowback-action/
I bought a 9mm kit from PSA a few years ago that I haven't put together yet. I'm guessing that it doesn't have an improved feed cone.
Probably not. However, I'd put it together and test it before doing anything. If it has problems feeding the ammo you choose, then it may be necessary to look into barrels with enhanced feed cones.
Man glad I found your video I am having problems with double fires and have replaced the trigger group. It’s a bear creek and I know you get what you pay for lol but it does have a regular buffer that it came with. Would you have any other suggestions or things to try?
I would just make sure to use a carbine-strength spring, a sliding weight buffer, and that the buffer+bolt mass is 22oz or more.
@@Blowback9 ok the one I ordered was I believe 8.3 with a flat carbine spring I also order the Wilson combat spring. I do not have a way to way them at the moment. Thank you for the response
@@Blowback9Iam having a feeding issue do u have a idea was going on I have the endo mags sometime double feed
Any experience running vltor a5 buffers?
Not directly, but reports are that they work for 9mm as-is in a carbine buffer tube since they're 4" long.
You're sharp
But, I do have a question with all this information great information how will the result be with a suppress system? Because that will be the main goal have it.
Adding a suppressor has the same effect as firing +P ammo. More blowback force. I'd use a heavier buffer, that's all. Everything else the same.
With the 4" buffer what length buffer tube do i need
Standard carbine buffer tube with a 4" buffer and 9mm bolt.
Thank you for the info!
Do you have a video on Rifle Length Buffers? Because I cant find a 9mm buffer made for a Rifle length buffer tube. I have a CTS Aktive buffer currently in my rifle. It weight 6.5 oz. I should be receiving my PSA Gen 4 9mm upper in a couple days. So I am hoping it works.
Im using a standard 556 lower..so i bought the sylvan arms magwell adapter and that has its own ejector that seems to be short..doesnt reach the top of the channel of the bcg. Is there a magwell adapter you can recommend that would work better and accept glock mags?
5 star videos
Doug, do you know any solutions for an ejector using a 5.56 lower without using the mag well insert kit? I know the Endo mags act as the ejector, but I like the fact the mag has to be in to eject a round.
Unfortunately, the only option I'm aware of is to use a magwell insert with the ejector attached.
@@Blowback9 thanks. With some research, I think the cmmg bolt would work too since it would have an ejector. But I would have to get their barrel also.