Chad, Thanks for taking the time to do this! I want to note, I did not stake or torque the castle nut in fear the lower ended up being total trash.....LOL. I didnt want to put the sauce to the end plate until we confirmed the lower to be usuable after encountering the blatant issues. This seemingly was the correct choice haha! Again, thank you! Always enjoy a solid learning experience! J
So what was the ending to this.. and due to the pins being oversized for the trigger can you or is there something to fix the issue at hand so it does not become dangerous in the long run.
@@SchooloftheAmericanRifle Hi, I have a lower that the bolt catch "channel" is out of spec. It is too wide and the bolt catch is loose. It doesn't hold the bolt back on last round anything I can do like fill it in with jb weld or something similar? It is a 17design lower and they're out of business now... I think I know why
I'll never buy a cosmetic blem again. I purchased a blem "matched" receiver set from a well respected company and the holes were so out of spec that I never used them. QC rejects with a scratch should not be sold as cosmetic blems but they regularly are. $300 in the toilet.
I have had great luck with bcm, and aero precision blems. In most cases its a tiny nick or scratch. But I agree if its out of spec than it should have been scrapped
@@aramirez8427 bins and racks of shame are somewhat extensive. Some of my own rifles are included. I won't fix certain things so I can show students how to find problems band what results from not fixing it.
@@KI.765you’re right but those problems should of been caught by someone else. That’s why this brand is supposed to be really expensive. Check and check again is what you are paying for.
The fact KAC charges people $300+ on a stripped lower while having stuff like this pass QC is inexcusable, guess this one just got tossed into the "blem" pile instead of the "trash" pile 🤷.
This channel is criminally underrated! I have enjoyed these videos tremendously! School of the American 🇺🇸 Rifle should be a mandatory class for high school students. Thank you for sharing your thoughts and knowledge in such a fantastic way. The camera angles are very good to show the viewer exactly what they need to see.
I recently found this channel and all I have to say is this is this guy is the Yoda of the modern rifle. As a former machinist turned USAF jet engine mechanic I can greatly appreciate every aspect of these videos. Insightful, articulate, educational.... keep it up! In fact, I think you should write a book! You could call it "The mechanics of the American rifle....learn it you must"
This is my continued experience with KAC. I have had multiple sr15s and sr16 components that have been all over the map with tolerances and finishing details. Definitely paying for the roll mark.
Why are you buying these crap guns? A Smith and Wesson M&P has better QC than these warmonger, anti- 2A contract companies. God forbid they sell guns to people that aren’t committing murder in random countries.
Be careful about buying during a panic buying period. QC gets rushed, machinery isn't shutdown for proper maintenance, and tooling gets run longer than recommended life cycles. Also increase in staff to fill orders means less experienced labor.
Really appreciate these videos. I don't think I've ever watched one and not learnt something new. You are doing your fellow Patriots a great service. I have an upper I'd love for you to go over. How would I do something like that?
In all the years watching gun channels and guys that claim to know their way around ARs this is the ONLY channel that actually shows his knowledge and process. It’s obvious that others are at best unknowingly shills and at worst complete shills. There are great brands but when guys act like good brands don’t fail it’s a lie. Thank you for what you do.
Having worked at an aluminum extruder for several years, and aerospace machine shop for several more, i can tell you with relieve certainty that the reason for the holes all being oversize is with the anodizer. First step in anodizing is a caustic stripping which removes about .001 per surface which makes holes get bigger, but the anodizing makes the surface 'grow' which puts everything close back to where it started, in a perfect scenario. If the caustic solution is brand new or if someone didn't follow the 'recipe' right, or if there was a problem with some parts that need to be striped and re anodized your hole sizes can get blown wide open in a hurry. The mag well being undersized is a completely different issue.
Then the tolerancing should be taking place after that procedure as well, or have the parts toleranced prior with that change in mind if they aren't willing to check twice
I used to work as a QE for an anodizing and plating company. While it is true that over etching or over anodizing can change dimensions, you'll usually see that all over the component. If all the other lower features are still in spec, it's likely that these specific holes were machinded out of spec or at the very bottom of the spec limit. Regardless, KAC should be verifying these AFTER anodizing - they should not have shipped this part.
I know this is an old video but just wanted to say I learned a lot from this video about the tolerance values for a lower receiver thanks to you! Thank you for showing all this valuable information!
@@davidschaadt5929 ya, over sized trigger pin holes or tight magwell ect are one thing; but the holes for the bolt catch being so big that it won't take the role pins is another. I expect scratches or some things to be slightly out of spec with blems, but still fully functional
@@muddyhotdog4103 Slop in the safety selector is an even bigger issue. You could assemble an inherently unsafe rifle with that, bolt catch is a convenience feature.
I have several of these KAC lowers, and honestly I have PSA lowers that are nicer. I sent one back and got a replacement from KAC because it would barely accept and drop a whole handful of mags. Super disappointing receiver given the manufacturer. Mine were also NOT marketed as blems.
@@KI.765 yes. Fingers crossed but I do want the truth even if it costs me money. No mercy just because I love KE Arms and In Range. I’m guessing it will absolutely pass and definitely be a solid win, but reality is a motherf$&ker!
I would be very interested in seeing that. I think probably it would pass, but a plastic lower is a real different beast from an aluminum one, there's got to be things one needs to pay attention to with that.
Yes, curious about how it would hold up. Mine appears to have a larger than normal gap between the upper and lower where the bolt meets the buffer tube, but not reliability issues at 700 rounds (BCM blem upper, Aero BCG, BA Hanson barrel). Would love to see him open one up.
I had a buddy that bought one of these lowers, and he encountered the exact same issues with the roll pin and magazine well issues. The Pmags we had would drop free, but the USGI aluminum mags we had on hand wouldn't. It was such a weird issue. He contacted KAC about it. They did send him a new lower but it took about a month for them to respond.
I love this channel. It just makes me more aware and cognizant of the details when building. thank you for your effort in putting out quality presentations.
I came across this channel a few weeks back. After watching the video suggested by youtube then, I subscribed without hesitation. This video is just as awesome as the past one. I love how in depth the explanations go. Keep up the good work.
I want to thank you for putting out these videos... they are a wealth of knowledge that no one else is producing at even close to the same level.. I have a knights ambi lower with a tight mag well, love the gun but the mag well not dropping most mags freely is aggravating to say the least
I always thought the term "blem" meant a cosmetic imperfection,which is what l have read on web pages.An out of spec hole shouldnt be considered a blem.That would be a deal breaker for me.Kinda misleading.
I love these videos. It goes to show that ALL manufacturers make mistakes, have various degrees of QC issues, and that we the end user are responsible for the purchases we make. What makes a company great isn't so much the mistakes or lack thereof, its how they remedy it and treat the customer.
Wow! I understand this is a sample size of one but a “blem” is a blemished item, a scratch or wrong color, poor anodizing and other cosmetic issues, not every single hole being oversized. KAC should be ashamed. This lower should’ve been melted and made into one of proper dimensions.
Right? Sample size of one, but still left a really bad taste in my mouth that that lower ever made it out the door. I wonder if they have the machinist tolerance check only every 5 or more lowers? Every CNC job I've had, we very rarely checked every part, just systematically every 3, 5, 10, ect., parts made.
Removing the selector arm properly is a testament to your knowledge, experience, skill, and most important, patience. It's learned, not taught. Hat's off to you.
What an incredibly educational video sheesh. I've just completed acquiring parts for a complete home build and I swear I learned more from watching this than everything I've read leading up to this lol. Great content and great camera work by the Mrs!
Ironically I just had a similar issue with a Griffin Armament blem lower I put together for my brother in law. The take-down pin detent spring hole wasn't drilled out. It was sold as a "cosmetic" blem, not a defective blem. I didn't realize it till I began assembling it and the spring wouldn't go beyond a quarter in the hole. Luckily it wasn't a big deal for me to bore it out with a simple hand drill; but most people who have no experience would have been screwed, or terrified to drill into the lower... It was a christmas gift for him, so there was no time to send it back to Griffin and frankly, the prospect of them doing anything was nill, since as Rainier told her, "you ordered a blem lower and they are sold as is"... which is true; but this wasn't a "cosmetic" blem; but rather an actual defect...
I can't believe the amount of slop that was built into a top tier lower. It should be replaced with a new one. It's funny that a friend of mine brought me his friends AR from a home build with a loose castle nut and buffer tube not timed right. Had to replace the keeper and spring and then you put this video out. Keep up the good work learning more everyday.
For all the 80% guy's out there , you opened my eyes with this video. Receiving inspection will be done before I make a gun that is maybe bad and I have to take a hammer too because it's a gun and can't be shipped back.
Chad, thanks for putting me onto Vibratite VC-3, I use it on my red dots on my pistols, have had them mounted for about a year with no movement, previously I'd need to remount them every 6-9 months with locktite, VC-3 works fantastically!
I have a 20-year-old Rock River lower that has a tight magwell, but it's a cool one because they did it on purpose so that GI mags wouldn't rattle around in the reciever. I can't use gen one p mags and gen 3 mags can sometimes require a shake to come free. Everything else is perfectly in spec though and the upper to lower lockup is solid.
very informative video for me I'm no gunsmith by any means I learn what to look for and have some insite on possible way to fix it or leave it or use a professional gunsmith ...I would not have thought about the safety not working properly and that's golden knowledge to have .
@@KI.765 it makes assembly / disassembly of the bolt catch SO much easier (especially if you’re a klutz like me). No banging in roll pins, no risk of scratching your lower. Aero also threads the takedown pin detent hole so you don’t have springs flying out if you remove the end plate.
@@KI.765 They have a threaded hole for the bolt catch. The most pain in the ass part of putting a lower parts kit into a lower is the roll pin for the bolt catch. You just screw in a threaded pin instead of using a long punch and hammer to drive it in. If the punch comes off the pin you most likely will put a big scratch down your lower if you don't put enough tape for insurance. Just makes life a little easier. Plus the M4e1 lower and M4e1 enhanced upper looks really nice. Has a billet look but still a forged receiver.
Love your videos, knowledge and advice, this lower could be replaced for less money than your costs to repair. But, yes, there are many ways you show to fix problems for these issues. Great to see this for fixes for SHTF type scenarios, otherwise this lower just needs to be replaced for longevity and increased functionality.
I learn so much from these videos. And this goes to show even the best which is kac, hodge, lmt, bcm etc... can be out of spec. Although rare, it happens. But learning the signs and symptoms helps the average owner a ton. Thanks sir
I use a lot of automotive plastic panel removers. I have some flat ones and some that have a nice bend for moments like that selector. I use them on cars first and when they get beat up I shape them and use them on smaller stuff like this. 🤙🏾
You are a great gunsmith and teacher I use Anderson lowers and some PSA the Anderson usually has never give me much trouble and mostly everything fits pretty good you have taught me a lot these high-dollar companies nowadays seems like just markup the money for the name they're not putting time in building the rifles undoubtedly are they have unexperienced workers
This makes me feel lucky with the "blem" receivers I've built so far, but after watching this video I don't think the savings is worth needing this much extra attention. Let's hope this is an extreme example.
FYI: a small string also is good for pulling levers if you don't have a plastic tool. Loop it around and pull. Tip is used by guitar and electronics techs to pull stubborn, and often rare knobs without causing damage..
Hi Chad. I hope you read this. I have had oversizing issues with my KAC lower as well. Mine is a non-ambi like this one except it was most certainly not sold as a blem. I have my suspicions that the company KAC has outsourced these lowers to are doing a very poor job, so I do not blame KAC in any way directly. However, I will try to bring this to their attention and my case as well.
Let the buyer beware , but as the host explained in the video , there are over sized pins available to make a fix . Which leads me to believe this is more common than you might believe .
These are absolutely _fascinating_ videos just to watch! Sadly firearms are heavily restricted in my country, but thankfully looking at them is not (yet)!!!
I'm sure KAC would make good on replacing this lower receiver. I would have at least contacted them, in a civil manner, to see what they had to say. Crap happens. I'd even settle for another "Blem", but with in spec safety switch holes this time, please. Love the videos. Doing great work here, SOTAR.
can you tell us about the go no go gages? and where to get them. maybe a video about them and other tools. im just starting gunsmithing school and your videos are a great resource.
Could you do a lower forge plant tour? On how these are born at the forge birth place? Like their has to be good and bad places that make these. But thank you for putting this on yt and enjoy just listening to the knowledge y’all provide.!! Have a safe Christmas during this trying times.!
I bought my SR-15 non-ambit lower in 2019 brand new and have the exact same issues. I use Geissele triggers and during dry fire you can see the trigger pins rotate inside the hole. They haven't come out yet surprisingly. The takedown pin holes are also big, same as in the video. Have to use a wedge in the rear to get it even close to snug. Magazines also usually do not drop free; only use Pmag M2/3 & Okay stanags. I have buddies that have the ambi lowers and they have the same issues with the magazines dropping. I can't imagine with the sample size and anecdotes that these are blems, they're just bad quality pawned off to civilians looking for a roll mark. That being said, the SR-15 uppers are incredible. Just the lowers are beyond pathetic.
For a company that really doesn’t offer much commercial it seems the commercial stuff they do roll out gets a ton of complaints. Makes me feel like I won the lottery with the upper I received. Also for 200 plus dollars. What a freaking rip off
Lol i'm not a just as gooder i'm CHEAP! I personally couldn't bare the thought that "my" $350 lower could possibly have more machining inconsistencies than a $30 lower. I understand quality of manufacturing materials is a thing. I am not ignorant I am cheap. Don't let my personal thoughts offend anybody. Just voicing my opinion on a vastly educational video.
Always great videos. For a gunsmith to fix properly costly for the customer, as you stated the company can assist or reject 🤔. Customer has to think about what is the best course of action.
Hey, I like these videos probably far more than I should. Also, just out of curiosity did you drill a hole in the handle end of a Delrin DPMS Takedown Pin Punch Tool to act as a starter for the Hammer / Trigger pins? That's a pretty slick idea. I know Geissele pins can be PITA if you use that D clip or whatever they call it.
Class III technical difficulties. :) Thanks for the information. Peaning the holes may give the lower added life. Not a great solution, but better than oversized.
I've had more problems with Anderson lowers with anything else...and I'm NOT talking about "blems". My first two Anderson's didn't have the selector detent hole drilled all the way through. I had to finish drilling them so the detents could reach the selector. They weren't sold as "blems". The next three were "cosmetic blems". The grip screw holes weren't drilled and tapped properly. The grip screws supplied with the Magpul MOE grips wouldn't tighter down all the way. Once I nicked the ends off the screws, they fit and tightened down fine. (None of those are life and liberty guns, even though they are solid.)
I understand the Anderson problems. KAC should have never put something like this out for sale. Most concerning thing were those oversized FCG pin and selector holes. Imagine if this went to a guy that has never owned or fired an AR and he wants to build his own. He wants top of the line and yes KAC is top shelf. He gets this lower, doesn't know any better and he thinks he has a fine in spec weapon. Over time and use you don't think it's possible for this lower to drop the hammer even when the selector is on safe?
@@Sman7290 I've built a lot of rifles at a lot of budgets, whether for myself or for friends getting in to shooting, and one thing I have found over the years is it really doesn't matter who's rollmark is on that receiver. Final QC on the "higher tier" parts is better, no doubt about it, usually surface finish or how "smooth" parts fit in, but the "budget" ones I've built have always worked without issue as well. I guess I may have been lucky, but I've never had even Anderson's out of spec with the guages I have, and I have no issue building one on top tier either.
A question about repairs to a reciver that has over sized FCG pin holes . I have a background as a machinist and also as a gunsmith. My question is is could a gunsmith using a mill and referencing off the FCG pin holes useing pinstock then mill the receiver to accommodate a steel or bronze threaded insert with a new set of FCG holes that are towards being undersized? Simmiular to the repairs done on aluminum injection molds where the threads stripped out of the aluminum and a steel insets are uset to put the mold back into Production or to improve the speed of mold assembly , or extend the life of the mold.
I had this exact same problem with a non-ambi SR-15 lower last year purchased in the fall. Mine was not as severe as this case. I contacted knights they sent me a brand new lower with no hassle. It was not a blem lower but they treated me very well. Just my .02
I bought a block and hold because you gave a discription of yours. Fantastic tool. Also JP has a really nice upper vice block - two piece. Check it out. I like mine way better than a reaction rod. Thank you for sharing your skills with us.
I play guitar and taking off volume and tone knobs can be a pain like that safety was. A trick I use is sliding a t-shirt or rag underneath the knob (or safety in this case) and using that as a tool to pull up on it. Might work well for this too.
Seems like the easiest and cheapest option to fix every problem is simply to swap lowers rather than getting oversized anti-walk pins and oversized receiver pins from JP which between all 4 pins will cost as much as a new lower. Even budget lowers like Anderson or PSA or Aero are consistently closer to spec than this.
Smdh I know it's a blem but KAC has alot of QC issues. Now when you do get a good on there is no doubt it will run like hell but dang I am starting to see and hear more and more QC issues at KAC.
This might have been the blems that was offered a few weeks ago on gundeals. I don't recall the vendor, but I remember the disclaimer was possible cosmetic issues , enlarge holes and undersize magazine wells.
I did not see in the comments nor did he mention but ALSO by having oversized trigger control group holes and an oversized selector hole you can be on semi and actually fire a burst if slowly pulling the trigger... the hammer will be riding the bolt home to accomplish this (usually 2-3 rounds before short stroking and not a good situation even if it sounds cool)
I bought a blem 80% lower, finished it out, and the bolt catch doesn't work. I tried several uppers, several BCGs, and 2 standard bolt catches and an expensive larger bolt catch. I am thinking the hole for the roll pin is drilled too low. With a metal magazine, it will catch the bolt & lock it to the rear, but barely. It's so low that dropping the magazine also makes the bolt slam home. I'm upset because it's my first 80% and I was happy with the job I did on it, only to find out that the finished portion of the receiver was done incorrectly.
Chad,
Thanks for taking the time to do this! I want to note, I did not stake or torque the castle nut in fear the lower ended up being total trash.....LOL. I didnt want to put the sauce to the end plate until we confirmed the lower to be usuable after encountering the blatant issues. This seemingly was the correct choice haha!
Again, thank you! Always enjoy a solid learning experience!
J
Thanks for the update. That's perfectly reasonable.
I'll be honest I'd be really angry if this was mine.
So what was the ending to this.. and due to the pins being oversized for the trigger can you or is there something to fix the issue at hand so it does not become dangerous in the long run.
Did Knight's Armament end up replacing it?
@@SchooloftheAmericanRifle
Hi, I have a lower that the bolt catch "channel" is out of spec. It is too wide and the bolt catch is loose. It doesn't hold the bolt back on last round anything I can do like fill it in with jb weld or something similar?
It is a 17design lower and they're out of business now... I think I know why
Selling blems is one thing, selling a mostly out of spec lower as a "blem" is entirely another.
KAC is lame change my mind.....
Blem should only be used for cosmetic blemish. Out of spec would be a more honest description.
It’s KAC man. C’mon you know.... an outrageously overpriced mil spec lower
I'll never buy a cosmetic blem again. I purchased a blem "matched" receiver set from a well respected company and the holes were so out of spec that I never used them. QC rejects with a scratch should not be sold as cosmetic blems but they regularly are. $300 in the toilet.
I have had great luck with bcm, and aero precision blems. In most cases its a tiny nick or scratch.
But I agree if its out of spec than it should have been scrapped
I really feel bad for the owner. This lower should not have been sold.
I will buy if from the owner of he decides to part with it.
@@4g63mark I'm tool and gauge poor, but it would be a good addition to my bins.
@@aramirez8427 bins and racks of shame are somewhat extensive. Some of my own rifles are included. I won't fix certain things so I can show students how to find problems band what results from not fixing it.
What is the best way to get a hold of you ?
Thanks Peter
@@SchooloftheAmericanRifle Bad parts are perfect examples to teach from.
Built on a Friday at 4:57 pm.
Or Monday morning first thing lol
People who haven't worked manufacturing will never understand how true that will always be. 😅
...At the tail end of the cutting tool life...
They must of had that machinist that couldn't read a micrometer! That boy ruined one heck of a lot of parts at the Rockwell axle plant!
@@KI.765you’re right but those problems should of been caught by someone else. That’s why this brand is supposed to be really expensive. Check and check again is what you are paying for.
This guy is the AR Doctor!!! I’ve learned so much about what makes a good AR build watching this channel!!!!
The fact KAC charges people $300+ on a stripped lower while having stuff like this pass QC is inexcusable, guess this one just got tossed into the "blem" pile instead of the "trash" pile 🤷.
they are $220 but your right.
It’s because KAC, Daniel, FN don’t care about 2A or consumers. They just want to sell SF guns to commit war crimes in random irrelevant countries.
@@MattfromFlorida-u5f$220 now maybe but $300 plus at times during Covid
This channel is criminally underrated! I have enjoyed these videos tremendously! School of the American 🇺🇸 Rifle should be a mandatory class for high school students. Thank you for sharing your thoughts and knowledge in such a fantastic way. The camera angles are very good to show the viewer exactly what they need to see.
Ur a criminal
I believe it is indicative of how shallow most people's relationship with their firearms are.
I recently found this channel and all I have to say is this is this guy is the Yoda of the modern rifle. As a former machinist turned USAF jet engine mechanic I can greatly appreciate every aspect of these videos. Insightful, articulate, educational.... keep it up! In fact, I think you should write a book! You could call it "The mechanics of the American rifle....learn it you must"
This is my continued experience with KAC. I have had multiple sr15s and sr16 components that have been all over the map with tolerances and finishing details. Definitely paying for the roll mark.
Why are you buying these crap guns? A Smith and Wesson M&P has better QC than these warmonger, anti- 2A contract companies. God forbid they sell guns to people that aren’t committing murder in random countries.
Be careful about buying during a panic buying period. QC gets rushed, machinery isn't shutdown for proper maintenance, and tooling gets run longer than recommended life cycles. Also increase in staff to fill orders means less experienced labor.
Really enjoyed the detail of this whole receiver.
KAC fanbois gonna come out violent on this one 🤣
Really appreciate these videos.
I don't think I've ever watched one and not learnt something new. You are doing your fellow Patriots a great service.
I have an upper I'd love for you to go over. How would I do something like that?
2nd. I have a JP BCG that does not function properly across platforms.
In all the years watching gun channels and guys that claim to know their way around ARs this is the ONLY channel that actually shows his knowledge and process. It’s obvious that others are at best unknowingly shills and at worst complete shills.
There are great brands but when guys act like good brands don’t fail it’s a lie.
Thank you for what you do.
Having worked at an aluminum extruder for several years, and aerospace machine shop for several more, i can tell you with relieve certainty that the reason for the holes all being oversize is with the anodizer.
First step in anodizing is a caustic stripping which removes about .001 per surface which makes holes get bigger, but the anodizing makes the surface 'grow' which puts everything close back to where it started, in a perfect scenario.
If the caustic solution is brand new or if someone didn't follow the 'recipe' right, or if there was a problem with some parts that need to be striped and re anodized your hole sizes can get blown wide open in a hurry.
The mag well being undersized is a completely different issue.
Then the tolerancing should be taking place after that procedure as well, or have the parts toleranced prior with that change in mind if they aren't willing to check twice
That makes some sense. Hard to envision the perfect storm of tooling issues for all those holes to be sloppy.
I used to work as a QE for an anodizing and plating company. While it is true that over etching or over anodizing can change dimensions, you'll usually see that all over the component. If all the other lower features are still in spec, it's likely that these specific holes were machinded out of spec or at the very bottom of the spec limit. Regardless, KAC should be verifying these AFTER anodizing - they should not have shipped this part.
yep
Bs. Anodizing didn't make the magwell outta spec.
As a DIY type, I have watched a lot of gun build videos and I gotta say, THIS one is the Apex of armor instructive videos. Thank you for making it.
I know this is an old video but just wanted to say I learned a lot from this video about the tolerance values for a lower receiver thanks to you! Thank you for showing all this valuable information!
Blems are still supposed to be fully functional.. I'd totally ask for a replacement.
Very true .
Also ,I can't believe all the problems with that thing .I like the "Stoner Rifle "marking .
@@davidschaadt5929 ya, over sized trigger pin holes or tight magwell ect are one thing; but the holes for the bolt catch being so big that it won't take the role pins is another. I expect scratches or some things to be slightly out of spec with blems, but still fully functional
@@muddyhotdog4103 Slop in the safety selector is an even bigger issue. You could assemble an inherently unsafe rifle with that, bolt catch is a convenience feature.
@@yunggolem4687 for sure
I have several of these KAC lowers, and honestly I have PSA lowers that are nicer. I sent one back and got a replacement from KAC because it would barely accept and drop a whole handful of mags. Super disappointing receiver given the manufacturer. Mine were also NOT marketed as blems.
You are very thorough, you are the kind of gunsmith I want working on my gun. Thanks for the lessons.
I like the fact you have inspection tools over and above the normal go/no go gauges, it shows the professionalism of your work.
Waiting for a physical on KE arms polymer lower 🙂
I'm interested in what the longevity of those will be.
@@KI.765 yes. Fingers crossed but I do want the truth even if it costs me money. No mercy just because I love KE Arms and In Range. I’m guessing it will absolutely pass and definitely be a solid win, but reality is a motherf$&ker!
I would be very interested in seeing that. I think probably it would pass, but a plastic lower is a real different beast from an aluminum one, there's got to be things one needs to pay attention to with that.
Meme lower made by commie sympathizers. No thanks.
Yes, curious about how it would hold up. Mine appears to have a larger than normal gap between the upper and lower where the bolt meets the buffer tube, but not reliability issues at 700 rounds (BCM blem upper, Aero BCG, BA Hanson barrel). Would love to see him open one up.
Side note for people who run into this issue is ELF has a drop in trigger that uses screw instead of pins to keep it in place. Great video.
Holy cow, you got some skills. Slapping that FCG in without a slave pin was impressive.
I had a buddy that bought one of these lowers, and he encountered the exact same issues with the roll pin and magazine well issues. The Pmags we had would drop free, but the USGI aluminum mags we had on hand wouldn't. It was such a weird issue. He contacted KAC about it. They did send him a new lower but it took about a month for them to respond.
I love this channel. It just makes me more aware and cognizant of the details when building. thank you for your effort in putting out quality presentations.
I came across this channel a few weeks back. After watching the video suggested by youtube then, I subscribed without hesitation.
This video is just as awesome as the past one.
I love how in depth the explanations go.
Keep up the good work.
Great video. You're expertise really shows. I found it interesting to see all your tools to gauge the tolerances.
I want to thank you for putting out these videos... they are a wealth of knowledge that no one else is producing at even close to the same level.. I have a knights ambi lower with a tight mag well, love the gun but the mag well not dropping most mags freely is aggravating to say the least
These videos are fascinating. You present the information very well.
I always thought the term "blem" meant a cosmetic imperfection,which is what l have read on web pages.An out of spec hole shouldnt be considered a blem.That would be a deal breaker for me.Kinda misleading.
And not just the bolt catch hole. Take down pins, fire control pins, extension tube. I guess we need to ask Why is is a blem.
I love these videos. It goes to show that ALL manufacturers make mistakes, have various degrees of QC issues, and that we the end user are responsible for the purchases we make. What makes a company great isn't so much the mistakes or lack thereof, its how they remedy it and treat the customer.
Wow! I understand this is a sample size of one but a “blem” is a blemished item, a scratch or wrong color, poor anodizing and other cosmetic issues, not every single hole being oversized. KAC should be ashamed. This lower should’ve been melted and made into one of proper dimensions.
Right? Sample size of one, but still left a really bad taste in my mouth that that lower ever made it out the door. I wonder if they have the machinist tolerance check only every 5 or more lowers? Every CNC job I've had, we very rarely checked every part, just systematically every 3, 5, 10, ect., parts made.
Removing the selector arm properly is a testament to your knowledge, experience, skill, and most important, patience. It's learned, not taught. Hat's off to you.
Totally, I have several of those selectors and the drilling-hole-to-drive-it-out trick would be a time saver.
Automotive trim removal tools also work well, they are plastic so non-marring, best $10 you can spend at Harbor Freight.
What an incredibly educational video sheesh. I've just completed acquiring parts for a complete home build and I swear I learned more from watching this than everything I've read leading up to this lol. Great content and great camera work by the Mrs!
Ironically I just had a similar issue with a Griffin Armament blem lower I put together for my brother in law. The take-down pin detent spring hole wasn't drilled out. It was sold as a "cosmetic" blem, not a defective blem. I didn't realize it till I began assembling it and the spring wouldn't go beyond a quarter in the hole. Luckily it wasn't a big deal for me to bore it out with a simple hand drill; but most people who have no experience would have been screwed, or terrified to drill into the lower... It was a christmas gift for him, so there was no time to send it back to Griffin and frankly, the prospect of them doing anything was nill, since as Rainier told her, "you ordered a blem lower and they are sold as is"... which is true; but this wasn't a "cosmetic" blem; but rather an actual defect...
I can't believe the amount of slop that was built into a top tier lower. It should be replaced with a new one. It's funny that a friend of mine brought me his friends AR from a home build with a loose castle nut and buffer tube not timed right. Had to replace the keeper and spring and then you put this video out. Keep up the good work learning more everyday.
For all the 80% guy's out there , you opened my eyes with this video. Receiving inspection will be done before I make a gun that is maybe bad and I have to take a hammer too because it's a gun and can't be shipped back.
Just mill them out right. Not that I’d know or anything I heard from a friend
Awesome channel. Thank you for your expertise and willingness to teach people. The fact that you teach us "trade secrets" is patriotic as hell 👍🇺🇸
Chad, thanks for putting me onto Vibratite VC-3, I use it on my red dots on my pistols, have had them mounted for about a year with no movement, previously I'd need to remount them every 6-9 months with locktite, VC-3 works fantastically!
I have a 20-year-old Rock River lower that has a tight magwell, but it's a cool one because they did it on purpose so that GI mags wouldn't rattle around in the reciever. I can't use gen one p mags and gen 3 mags can sometimes require a shake to come free. Everything else is perfectly in spec though and the upper to lower lockup is solid.
very informative video for me I'm no gunsmith by any means I learn what to look for and have some insite on possible way to fix it or leave it or use a professional gunsmith ...I would not have thought about the safety not working properly and that's golden knowledge to have .
Awesome video! If I was the owner I would send it back with a copy of the video! KAC is not cheap, this is what you expect from Anderson !
You’re so thorough, and do amazing work! Love the videos they’re awesome. Keep it up man!
Blems should be cosmetic not functional. Companies shouldn't sell lowers like this.
I stumbled app on your channel while studying for a gun smithing cert have to say your videos are a great help and supplement to my classes
I love my AERO M4e1 lowers. Those are the only ones I buy. The threaded bolt catch is best thing since sliced bread.
Not saying it's not great, but how does it help or what does it improve?
@@KI.765 it makes assembly / disassembly of the bolt catch SO much easier (especially if you’re a klutz like me). No banging in roll pins, no risk of scratching your lower.
Aero also threads the takedown pin detent hole so you don’t have springs flying out if you remove the end plate.
@@KI.765 They have a threaded hole for the bolt catch. The most pain in the ass part of putting a lower parts kit into a lower is the roll pin for the bolt catch. You just screw in a threaded pin instead of using a long punch and hammer to drive it in. If the punch comes off the pin you most likely will put a big scratch down your lower if you don't put enough tape for insurance. Just makes life a little easier. Plus the M4e1 lower and M4e1 enhanced upper looks really nice. Has a billet look but still a forged receiver.
I rebuilt M61A1 Vulcan's for the USAF and their nomenclature for the "split pin" is spring pin, and the "spiral" pin is what they called a roll pin.
I guess I should invest in a set of gauges if I’m going to be finishing 80% lowers. I’m going to reference this vid for years to come. Thank sit🙏🏽
Props to your wife for the camera work. I kept thinking you had three hands.
Love your videos, knowledge and advice, this lower could be replaced for less money than your costs to repair. But, yes, there are many ways you show to fix problems for these issues. Great to see this for fixes for SHTF type scenarios, otherwise this lower just needs to be replaced for longevity and increased functionality.
I learn so much from these videos. And this goes to show even the best which is kac, hodge, lmt, bcm etc... can be out of spec. Although rare, it happens. But learning the signs and symptoms helps the average owner a ton. Thanks sir
I use a lot of automotive plastic panel removers. I have some flat ones and some that have a nice bend for moments like that selector. I use them on cars first and when they get beat up I shape them and use them on smaller stuff like this. 🤙🏾
well, after two videos on this channel, I realize I know little to nothing on the AR platform.
Subscribed.
You are a great gunsmith and teacher I use Anderson lowers and some PSA the Anderson usually has never give me much trouble and mostly everything fits pretty good you have taught me a lot these high-dollar companies nowadays seems like just markup the money for the name they're not putting time in building the rifles undoubtedly are they have unexperienced workers
This makes me feel lucky with the "blem" receivers I've built so far, but after watching this video I don't think the savings is worth needing this much extra attention. Let's hope this is an extreme example.
Id LOVE to see an Aero tested
FYI: a small string also is good for pulling levers if you don't have a plastic tool. Loop it around and pull. Tip is used by guitar and electronics techs to pull stubborn, and often rare knobs without causing damage..
I use thin monofilament… always works great.
Hi Chad. I hope you read this.
I have had oversizing issues with my KAC lower as well. Mine is a non-ambi like this one except it was most certainly not sold as a blem. I have my suspicions that the company KAC has outsourced these lowers to are doing a very poor job, so I do not blame KAC in any way directly. However, I will try to bring this to their attention and my case as well.
I really can't understand why they would put these out on the market, "blem" or not.
Um....
Have you seen the price tag on KAC anything? They could sell used toilet paper with their logo on it and people will pay top dollar
Because even as a blem it is still higher quality than most cheap receivers out there?
Let the buyer beware , but as the host explained in the video , there are over sized pins available to make a fix . Which leads me to believe this is more common than you might believe .
@@hellcatdave1 lmao. Higher quality. Did we watch the same video?
Thanks for the video,Steel is had to beat,My M1 was made in 43 and still sending rounds down range.
These are absolutely _fascinating_ videos just to watch! Sadly firearms are heavily restricted in my country, but thankfully looking at them is not (yet)!!!
Fascinating video today. Learned a lot.
Love the threaded pins. It takes the angst out of my builds. Im not a pro and I have scratched a lower before getting the pins in.
I'm sure KAC would make good on replacing this lower receiver. I would have at least contacted them, in a civil manner, to see what they had to say. Crap happens. I'd even settle for another "Blem", but with in spec safety switch holes this time, please.
Love the videos. Doing great work here, SOTAR.
can you tell us about the go no go gages? and where to get them. maybe a video about them and other tools. im just starting gunsmithing school and your videos are a great resource.
your thoroughness is amazing
Could you do a lower forge plant tour? On how these are born at the forge birth place? Like their has to be good and bad places that make these.
But thank you for putting this on yt and enjoy just listening to the knowledge y’all provide.!!
Have a safe Christmas during this trying times.!
Your channel is a gem! A treasure trove of information! Thank you for the outstanding content! Also special thanks to you assistant!
I bought my SR-15 non-ambit lower in 2019 brand new and have the exact same issues. I use Geissele triggers and during dry fire you can see the trigger pins rotate inside the hole. They haven't come out yet surprisingly.
The takedown pin holes are also big, same as in the video. Have to use a wedge in the rear to get it even close to snug.
Magazines also usually do not drop free; only use Pmag M2/3 & Okay stanags. I have buddies that have the ambi lowers and they have the same issues with the magazines dropping. I can't imagine with the sample size and anecdotes that these are blems, they're just bad quality pawned off to civilians looking for a roll mark.
That being said, the SR-15 uppers are incredible. Just the lowers are beyond pathetic.
For a company that really doesn’t offer much commercial it seems the commercial stuff they do roll out gets a ton of complaints. Makes me feel like I won the lottery with the upper I received.
Also for 200 plus dollars. What a freaking rip off
You're paying for factory stampings and that's about it. Anderson blems for the win. $29.99 all day baby
@@anthonysmalawipredators8794 lmao. "Just as good."
@@anthonysmalawipredators8794 that's not an accurate statement.
@@benw4401 whatever you have to say to justify overpaying, more power to you.
Lol i'm not a just as gooder i'm CHEAP! I personally couldn't bare the thought that "my" $350 lower could possibly have more machining inconsistencies than a $30 lower. I understand quality of manufacturing materials is a thing. I am not ignorant I am cheap. Don't let my personal thoughts offend anybody. Just voicing my opinion on a vastly educational video.
Some cheap 3M Bondo 357 spreaders cut down would also help you remove safety's like these with out scratching anything .
Always great videos. For a gunsmith to fix properly costly for the customer, as you stated the company can assist or reject 🤔. Customer has to think about what is the best course of action.
The Poor's are gonna love this!
Great Video! Not many out there showing how to tap/thread the bolt catch pin area would you reconsider putting it out there on the YT?
Excellent. Video. I really enjoy your lessons. I have learned so much. Thank you.
Hey, I like these videos probably far more than I should. Also, just out of curiosity did you drill a hole in the handle end of a Delrin DPMS Takedown Pin Punch Tool to act as a starter for the Hammer / Trigger pins?
That's a pretty slick idea. I know Geissele pins can be PITA if you use that D clip or whatever they call it.
That punch device is made by obsidian arms. It's delrin. Really neat tool they include with punch sets.
I understood some of these words. I would give my left nut to be an apprentice to a smith of his class.
WOW KAC...😬
What are your views on ratcheting castle nuts?
Class III technical difficulties. :)
Thanks for the information.
Peaning the holes may give the lower added life. Not a great solution, but better than oversized.
Love your videos
Wish I could take your classes but for now your videos have helped me immensely.
12:35 First thought is they used a #20 drill, and that seems to be the case. 0.161 gauge would go in, but be tight.
Glad I bought an Anderson!
But seriously, why would KAC sell that even as a blem?
Companies are desperate, ive bought 10 different parts for my AR this year and all have come with some kind of finish blem. Sucks
I've had more problems with Anderson lowers with anything else...and I'm NOT talking about "blems".
My first two Anderson's didn't have the selector detent hole drilled all the way through. I had to finish drilling them so the detents could reach the selector. They weren't sold as "blems".
The next three were "cosmetic blems". The grip screw holes weren't drilled and tapped properly. The grip screws supplied with the Magpul MOE grips wouldn't tighter down all the way. Once I nicked the ends off the screws, they fit and tightened down fine.
(None of those are life and liberty guns, even though they are solid.)
I understand the Anderson problems. KAC should have never put something like this out for sale. Most concerning thing were those oversized FCG pin and selector holes.
Imagine if this went to a guy that has never owned or fired an AR and he wants to build his own. He wants top of the line and yes KAC is top shelf. He gets this lower, doesn't know any better and he thinks he has a fine in spec weapon. Over time and use you don't think it's possible for this lower to drop the hammer even when the selector is on safe?
@@Sman7290 I've built a lot of rifles at a lot of budgets, whether for myself or for friends getting in to shooting, and one thing I have found over the years is it really doesn't matter who's rollmark is on that receiver. Final QC on the "higher tier" parts is better, no doubt about it, usually surface finish or how "smooth" parts fit in, but the "budget" ones I've built have always worked without issue as well. I guess I may have been lucky, but I've never had even Anderson's out of spec with the guages I have, and I have no issue building one on top tier either.
A question about repairs to a reciver that has over sized FCG pin holes . I have a background as a machinist and also as a gunsmith. My question is is could a gunsmith using a mill and referencing off the FCG pin holes useing pinstock then mill the receiver to accommodate a steel or bronze threaded insert with a new set of FCG holes that are towards being undersized? Simmiular to the repairs done on aluminum injection molds where the threads stripped out of the aluminum and a steel insets are uset to put the mold back into Production or to improve the speed of mold assembly , or extend the life of the mold.
Harbor Freight sells plastic trim and molding tool set that would work great for removing that selector.
What gauges do you use? Appreciate all the great info!
I had this exact same problem with a non-ambi SR-15 lower last year purchased in the fall. Mine was not as severe as this case. I contacted knights they sent me a brand new lower with no hassle. It was not a blem lower but they treated me very well. Just my .02
Inspectors pencil whipping their first articles, and machinists not checking their parts. Gotta love it.
Great vid. Wish there were more teachers like you. Very thorough. 5 star.
You have the best chanel. Where do i buy these tools and will you give up a list of tools specific to AR 10?
Thank you for everyone of these videos I’ve learned so much from your content.
I bought a block and hold because you gave a discription of yours. Fantastic tool. Also JP has a really nice upper vice block - two piece. Check it out. I like mine way better than a reaction rod. Thank you for sharing your skills with us.
I play guitar and taking off volume and tone knobs can be a pain like that safety was. A trick I use is sliding a t-shirt or rag underneath the knob (or safety in this case) and using that as a tool to pull up on it. Might work well for this too.
String also works. Learned from a vintage amp tech. -Fellow guitarist.
Just noticed the Sriracha hot sauce bottle repurposed as a lube bottle. I do the same! Lol
Omg size the pin drill the bolt catch done ✅. But customer is always right. I understand
Seems like the easiest and cheapest option to fix every problem is simply to swap lowers rather than getting oversized anti-walk pins and oversized receiver pins from JP which between all 4 pins will cost as much as a new lower. Even budget lowers like Anderson or PSA or Aero are consistently closer to spec than this.
Smdh I know it's a blem but KAC has alot of QC issues. Now when you do get a good on there is no doubt it will run like hell but dang I am starting to see and hear more and more QC issues at KAC.
What causes a lower to be this out of spec? Worn out CNC bits, or drill bits? I agree with other posters. This should not have left KAC.
This might have been the blems that was offered a few weeks ago on gundeals. I don't recall the vendor, but I remember the disclaimer was possible cosmetic issues , enlarge holes and undersize magazine wells.
I've learned so much from your videos! Thank you!!
I did not see in the comments nor did he mention but ALSO by having oversized trigger control group holes and an oversized selector hole you can be on semi and actually fire a burst if slowly pulling the trigger... the hammer will be riding the bolt home to accomplish this (usually 2-3 rounds before short stroking and not a good situation even if it sounds cool)
I bought a blem 80% lower, finished it out, and the bolt catch doesn't work. I tried several uppers, several BCGs, and 2 standard bolt catches and an expensive larger bolt catch. I am thinking the hole for the roll pin is drilled too low. With a metal magazine, it will catch the bolt & lock it to the rear, but barely. It's so low that dropping the magazine also makes the bolt slam home. I'm upset because it's my first 80% and I was happy with the job I did on it, only to find out that the finished portion of the receiver was done incorrectly.