Geissele should give you royalties. I bet this video has sold a LOT of geissele bcgs. I just shelled out the currency in modern day dollars for this bolt carrier group and this video is what ultimately sold me. Very much looking forward to opening the mailbox next week!
I appreciate the video and the way you go about inspecting and reviewing products. Very professional and well executed. Appreciate the humility even though you clearly know what you’re talking about.
@@bidenisatraitor7633 How the staking looks is like the least important part of the bolt carrier yet the one everyone gets the most butthurt about. If the screws can’t turn then the staking is doing its job.
@@bidenisatraitor7633 you said it was staked just not well. Is it a nitrided carrier? If so there’s no way to stake it very well after the surface treatment due to the hardness. But if there’s material impinging on the screws at all then they’re not going to turn on their own during normal use. They’ll break free with a wrench at a lower torque sure, but good enough is good enough. I’ve got a nitrided Aero BCG, and the staking isn’t deep, but it’s more than enough to prevent the screws from rotating. Young manufacturing doesn’t stake the keys at all, they just apply a threadlocker that stops working at high temperatures. And even then the worst that I’ve heard of happening is some gas leakage. If the gas keys are staked and there’s material impinging on the screws then it’ll be fine.
Yoda holding an AR15 - "hmmmmm could be" a good tattoo. I totally agree he is the Yoda of his chosen profession, by far floating in another place we want to be.
You're one of the only ones I've seen address the 3 IDs inside the Bolt Carrier. Most people are totally unaware of these critical dimensions. Bill Alexander brought them to my attention about a decade ago and how important they are for the gas system.
@@tommcfarland5368 Seriously! Matel.....given the year....late 50's. They were a cutting edge plastics toy company doing hollow core moldings. The exact technology they wanted... 🤠 Back in the day....my toy gun or MATEL rifle were common fair.
@tthams73 You won't have reliability issues if the BCGs are held to specs, the gas blocks are tightly-fit, chambers are cut correctly, good mags and ammo, well-lubed.
expensive, yes. great, yes!!! these Geissele BCG's are excellent for a solid ar-15 build i got one early this year and its smooth and reliable, no issues to date, have about 800 rounds using various 55-77 grain ammo and runs like a swiss pocket watch. 👍👍👍
I liked mine so much in my geissele superduty I bought one for my bcm . If they have a good deal this black Friday I might get another for my Daniel defense I really don't like phosphate bcm's.
@@USAMAXI42069, I now have close to 8,000 ish rounds on mine and it is still running great. Coating is awesome. Cleans very easily. No real signs of excessive wear.
The Godfather of ARs teaches again. You channel is the best for this kind of work. Now I feel like I know absolutely nothing. Glad I can learn from here.
Important to note Geissele sells two BCG, the one you have here is the high end Reliability Enhanced Bolt Carrier Group (REBCG) model, not the cheaper Bolt Carrier Group, M4A1 many in the comments are referring to.
This much I know; if I ever need a BCG this is the one to purchase. I know that this is test sample of one, but I haven’t seen another first piece inspection sample that there is something better out there.
You and @AvE are the best channels. I don't know why but I can watch these all day. (also if you guys like stuff like this but with tools, check out AvE's page) now i'm onto your next video!
Top bad AvE slowed down his tool video output. He still throws stuff up occasionally, but not at the regularity/frequency he once did. Particularly the BOLTR vids.
keep these coming, if you make enough i'll finally be able to build a rifle that I know is excellent vs assuming it is based on forums and gun store guy's advice which never go into anywhere near this level of detail.
I'm digging the "physicals" & "autopsys"..... besides the proprietary coating and tight tolerances, what makes the Geissle BCG "enhanced" ? Say as compared to the Surefire BCG which has all kinds of modifcations. Not saying that one is better, just curious if Geissle made any other changes like chanfing the cam pin travel... etc
I think Geissele extended the rails that contact and slide against the inside of the upper receiver all the way forward to the front edge of the carrier instead of to just a few millimeters forward of the cam pin track. Not sure if there's anything else besides that.
Besides the extended upper rails, and nano weapon coating. It's essentially just a super high quality BCG. High quality materials, tight tolerances where necessary, high level of finish, and high level of QC. This thing is meant to just perform all day long, whether a match gun, or a full auto setup, without any issues. Outlast other mil-spec BCGs, and be super easy to clean. Not sure what else you need from a quality duty BCG. If you want to get into more exotic stuff, and tune stuff for very specific use cases, with like lightened BCGs for race guns, this might be for you. If you want one of the best, and super reliable, duty level BCGs, hard to do better.
Wish you would use the bore scope to see how rough smooth the gas ring run on the inside is like you have done on others in the past. Regardless you make the best most educational videos on UA-cam and probably the whole internet!
Can I please ask where I can acquire these gauging tools. I am both a tool junkie and a gun junkie and your videos are like crack. I'm truly fascinated by these gauges.
They've changed the cam pin on the rebcg. Mine on my SD pistol and rifle looks very different. The cam has an arrow etched into it and one side has a raised lip. It's a trapezoid, kinda.
Is it possible that the small groove he found. Where the hammer is cocked was from a few possible test fires of the bolt? For a BCG of that price, I'd 100% expect it was test fired and HPT
Do you think that groove on the bottom of the boat carrier group is designed to progressively set the hammer and be less aggressive in contact with the trigger group?
HOLY S*&T!!!! THAT IS THE BEST VIDEO I HAVE EVER SEEN ON BCG!!! YOU FOR SURE JUST GOT A NEW SUBSCRIBER, ME!! YOU ARE AWESOME. So do you sell those gauges? i will have to look into your school. That would be AWESOME to learn from you.
Doesn’t surprise me, Geissele makes quality stuff. I just shot a 11.5 pistol and it was an absolute dream to shoot it was extremely soft shooting and felt like it was gassed perfect! It was also very very accurate at the 25 yards I shot it at but I’d be willing to bet the one i shot was definitely sub MOA.
400 plus rounds through my geissele super duty 11.5" i bought last month. only have a 50 yard indoor range but grouping is nice. i need a 3x micro to see farther to get it splitting crosshairs at longer distances. i can hit the little side target every time at 50 yards though. great tool
Geissele Colt bcg.I've researched and they are Colt bcgs.Colt might not be too popular right now but I have 2 m4a1socoms and a Geissele Urg-i and they are fantastic,accurate and reliable.
Made several mentions/comparisons to Colt. I like that. What he didn't say is that Colt BCG is (approx. Sept. 2024) $185.00 and the Geissele BCG is listed at $350.00 or more. Get a Colt.
$385! Sons of liberty gun works bcg is just as if not better, for $179.... Geissele although makes fantastic parts for my pew and I have ALOT of their stuff. It is kinda, ok alot overpriced.
Is there a gauge that checks the concentricity of the 3 ID bores inside the bolt carrier? Although you did check the diameter of each there could still be an issue of concentricity to each other which could cause the bolt to bind. However, simply moving the bolt in and out of the carrier may be a sufficient check.
Would love to see a check on their new rifles which have had a lot of issues with machining and coating, to see if their internals function properly. Thanks for the great content Chad.
YFS screws are made in Taiwan. They are a lower cost option for screws (and tend to be lower quality). They have a tendency to break and/or come lose on a regular basis. Considering the forces and psi that the BCG has to contend with, lower quality is not what you want on a fighting rifle.
As stated above, yfs screws are low quality. They can shear right off the carrier. They're fine for handguards and such though. You'll find them on the budget of the budget bcgs. I saw a set on a Wilson Combat bcg and I was very disappointed
Did you say "Gold" spring?? I'm not gonna pretend like I know why that exists but I use to work in metal fab and I can without a doubt tell you a gold spring will not hold its resistance as long as even an aluminum spring... seems like a major gimic, can someone please explain?
My Heissele Super Duty Pistol hasn't been cycling properly lately. It will work fine right after cleaning for the first couple of mags, then I have to manually pull the charging handle back each time to eject the round to chamber the new one. Sometimes it will eject the old round but not chamber a new one.
One of the worst things you can do to a bolt is HPT it. Terrible for the life of the bolt, but Geissele is using forgings for their bolts now, which should increase the strength considerably.
I’ve been searching for this bcg. The ones I’m finding don’t have the REBCG marking underneath the Geissele marking. Does anyone know why or seen the same? I don’t want to get a knock off or idk if the pic they are using is accurate.
not sure if you did any digging or not, but the standalone REBCGs are sold with a standard cam pin. however, the REBCGs that come in complete uppers have a proprietary directional cam pin and the Duty/Super Duty line of upper receivers are machined for the different cam pin
additionally, the directional cam pin will only function in a Super Duty upper. but any old BCG will also function perfectly fine in the SD upper receiver. the proprietary cam pin in the REBCG can be swapped out for a standard cam pin so that it will work in any milspec upper
More specifically, if magnetic, then cleaning becomes a real problem because wear particles from the ferrous metal parts will stick to the magnetized parts. Even a full degreasing teardown may not entirely remove all the bits.
Why did Geisselle use the extractor spring donut AND the insert with a gold spring. Should've discarded the donut, just adds more pressure to the extractor.
Geissele should give you royalties. I bet this video has sold a LOT of geissele bcgs. I just shelled out the currency in modern day dollars for this bolt carrier group and this video is what ultimately sold me. Very much looking forward to opening the mailbox next week!
@@5jjtmine ran me close to four a few weeks ago
I found this video educating and relaxing. Thanks dude
I'm no engineer, but man...I really enjoy these videos. Thank you for taking the time to put them together!
I appreciate the video and the way you go about inspecting and reviewing products. Very professional and well executed. Appreciate the humility even though you clearly know what you’re talking about.
Imagine how many guys are now mental about their BCG's after watching these videos. I liked hearing how he compared this particular bcg to Colt.
I compared my colt to.my aero...and the colt is a fine piece...the aero staking is junk. Colt knows how to do it.
@@bidenisatraitor7633 How the staking looks is like the least important part of the bolt carrier yet the one everyone gets the most butthurt about. If the screws can’t turn then the staking is doing its job.
@@JohnMaxGriffin well if it's not staked well who's to say they won't turn?
@@bidenisatraitor7633 you said it was staked just not well. Is it a nitrided carrier? If so there’s no way to stake it very well after the surface treatment due to the hardness. But if there’s material impinging on the screws at all then they’re not going to turn on their own during normal use. They’ll break free with a wrench at a lower torque sure, but good enough is good enough.
I’ve got a nitrided Aero BCG, and the staking isn’t deep, but it’s more than enough to prevent the screws from rotating.
Young manufacturing doesn’t stake the keys at all, they just apply a threadlocker that stops working at high temperatures. And even then the worst that I’ve heard of happening is some gas leakage. If the gas keys are staked and there’s material impinging on the screws then it’ll be fine.
This guy is the Yoda of ar15s
He just needs to start talking like Yoda.
Yoda holding an AR15 - "hmmmmm could be" a good tattoo. I totally agree he is the Yoda of his chosen profession, by far floating in another place we want to be.
"This is the way"....
If your life depends on it, Geissele is the best.
And I’m here like a 2024 Hattori Hanzo with Google Translate. 🫡
You're one of the only ones I've seen address the 3 IDs inside the Bolt Carrier. Most people are totally unaware of these critical dimensions. Bill Alexander brought them to my attention about a decade ago and how important they are for the gas system.
@@rifleshooterchannel208 Correct. They manufactured the plastic furniture for the AR15 and M16 I believe.
@@hellcatdave1 mattel, the toy maker?? Seriously??
@@tommcfarland5368 Seriously! Matel.....given the year....late 50's. They were a cutting edge plastics toy company doing hollow core moldings.
The exact technology they wanted... 🤠
Back in the day....my toy gun or MATEL rifle were common fair.
@tthams73 You won't have reliability issues if the BCGs are held to specs, the gas blocks are tightly-fit, chambers are cut correctly, good mags and ammo, well-lubed.
expensive, yes. great, yes!!! these Geissele BCG's are excellent for a solid ar-15 build i got one early this year and its smooth and reliable, no issues to date, have about 800 rounds using various 55-77 grain ammo and runs like a swiss pocket watch. 👍👍👍
come back at 8000 lol
Yeah. 99% of BCGs will run 800 rounds. Run it to the least 5000 and then let us know :)
I liked mine so much in my geissele superduty I bought one for my bcm . If they have a good deal this black Friday I might get another for my Daniel defense I really don't like phosphate bcm's.
@@USAMAXI42069, I now have close to 8,000 ish rounds on mine and it is still running great. Coating is awesome. Cleans very easily. No real signs of excessive wear.
may you do a video on: 1) overall most reliable AR & least reliable (or ARs that come across ur desk the most with poor marks?) 2) Best & Worst BCGs?
I really like that you did a physical on a new BCG. It amounts to the best type of review possible, where you look at the quality at a micro level.
Currently in engineering classes for my major.
This is some high quality po'rn.
All this tells me is Geissele makes amazing stuff if ya willing to pay for it.
The Godfather of ARs teaches again. You channel is the best for this kind of work. Now I feel like I know absolutely nothing. Glad I can learn from here.
Holy shit you should be the director of QA for a major manufacturer...
Important to note Geissele sells two BCG, the one you have here is the high end Reliability Enhanced Bolt Carrier Group (REBCG) model, not the cheaper Bolt Carrier Group, M4A1 many in the comments are referring to.
Man I didn't realize you guys were somewhat close to me . I'm in Harper's Ferry WV. I need to come to one if your guys classes man .
A fellow mountaineer!!
If I was local I'd be attending classes as often as possible.
This much I know; if I ever need a BCG this is the one to purchase. I know that this is test sample of one, but I haven’t seen another first piece inspection sample that there is something better out there.
9:35 What was going on with the calipers and the paper towel?
Outstanding level of detailed examination. I'm learning from watching!
You and @AvE are the best channels. I don't know why but I can watch these all day. (also if you guys like stuff like this but with tools, check out AvE's page) now i'm onto your next video!
Top bad AvE slowed down his tool video output. He still throws stuff up occasionally, but not at the regularity/frequency he once did. Particularly the BOLTR vids.
keep these coming, if you make enough i'll finally be able to build a rifle that I know is excellent vs assuming it is based on forums and gun store guy's advice which never go into anywhere near this level of detail.
This channel is always so on point and its wonderful
I'm digging the "physicals" & "autopsys"..... besides the proprietary coating and tight tolerances, what makes the Geissle BCG "enhanced" ? Say as compared to the Surefire BCG which has all kinds of modifcations. Not saying that one is better, just curious if Geissle made any other changes like chanfing the cam pin travel... etc
I think Geissele extended the rails that contact and slide against the inside of the upper receiver all the way forward to the front edge of the carrier instead of to just a few millimeters forward of the cam pin track. Not sure if there's anything else besides that.
Another thing Geissele is very proud of is their nanoweapon coating.
It has a forged carpenter 158 plus bolt that is supposed to last five times as many rounds along with the nitrided hard chrome finish.
Besides the extended upper rails, and nano weapon coating. It's essentially just a super high quality BCG. High quality materials, tight tolerances where necessary, high level of finish, and high level of QC. This thing is meant to just perform all day long, whether a match gun, or a full auto setup, without any issues. Outlast other mil-spec BCGs, and be super easy to clean. Not sure what else you need from a quality duty BCG. If you want to get into more exotic stuff, and tune stuff for very specific use cases, with like lightened BCGs for race guns, this might be for you. If you want one of the best, and super reliable, duty level BCGs, hard to do better.
Thank you for showing this. Your logo is Awesome to.
Just got hooked on your videos love watching them - Please keep up the good work..:)
It’s hard not to be a Geiselle fan boy!!!! I have never got anything but excellent products from them!!!!
Wish you would use the bore scope to see how rough smooth the gas ring run on the inside is like you have done on others in the past. Regardless you make the best most educational videos on UA-cam and probably the whole internet!
Fascinating absolutely fascinating
Geissele is a top tier brand, expected to pass with flying colors for the price of that BCG.
Can I please ask where I can acquire these gauging tools. I am both a tool junkie and a gun junkie and your videos are like crack.
I'm truly fascinated by these gauges.
facebook.com/groups/sotar/?ref=share
Brownell's has at least most of them.
Im binge watching these videos for the past 2 days😂. Thats for the info playboy
They've changed the cam pin on the rebcg. Mine on my SD pistol and rifle looks very different. The cam has an arrow etched into it and one side has a raised lip. It's a trapezoid, kinda.
Yeah and it won't work in another upper unless you switch the pin
Is it possible that the small groove he found. Where the hammer is cocked was from a few possible test fires of the bolt?
For a BCG of that price, I'd 100% expect it was test fired and HPT
Love your channel, I was wanting to know where you get all your gauges at for your measuring of components.
Awesome work. Really appreciate the content you’re providing!
You think these are worth the cost increase over the standard geissele bcg?
I saw bill geiselle say the testing they did for 20,000 rounds on a BCG with no issues and he swears they can get a 100,000 rounds with no issues.
Hello you didn't bore scope the Geisseley bolt carrier
Do you think that groove on the bottom of the boat carrier group is designed to progressively set the hammer and be less aggressive in contact with the trigger group?
HOLY S*&T!!!! THAT IS THE BEST VIDEO I HAVE EVER SEEN ON BCG!!! YOU FOR SURE JUST GOT A NEW SUBSCRIBER, ME!! YOU ARE AWESOME. So do you sell those gauges? i will have to look into your school. That would be AWESOME to learn from you.
Doesn’t surprise me, Geissele makes quality stuff. I just shot a 11.5 pistol and it was an absolute dream to shoot it was extremely soft shooting and felt like it was gassed perfect! It was also very very accurate at the 25 yards I shot it at but I’d be willing to bet the one i shot was definitely sub MOA.
400 plus rounds through my geissele super duty 11.5" i bought last month. only have a 50 yard indoor range but grouping is nice. i need a 3x micro to see farther to get it splitting crosshairs at longer distances. i can hit the little side target every time at 50 yards though. great tool
Awesome channel, thanks for taking the time to make these videos!
11:33 How common is a BCG that does not take the Yellow gauge?
Do you think that groove on the bottom of the boat carrier could be to reset the trigger more gently and induce less wear?
Very interesting. Thanks for your time!
I think my next BCG will be a Giessele.
Geissele Colt bcg.I've researched and they are Colt bcgs.Colt might not be too popular right now but I have 2 m4a1socoms and a Geissele Urg-i and they are fantastic,accurate and reliable.
@@realisrealite5554 Care to share your research?
@@realisrealite5554 they used to use Colt BCGs. Not anymore, they're made in-house.
Be ready to pay 400 bucks...
Awesome content sir. Learned many new things. Thanks
I like your smithing tools, where did you get them from?
Very informative as always. 👍😎👍🇺🇸💯
Made several mentions/comparisons to Colt. I like that. What he didn't say is that Colt BCG is (approx. Sept. 2024) $185.00 and the Geissele BCG is listed at $350.00 or more. Get a Colt.
$385! Sons of liberty gun works bcg is just as if not better, for $179.... Geissele although makes fantastic parts for my pew and I have ALOT of their stuff. It is kinda, ok alot overpriced.
Looking forward to your next video
..... hope all is well!
Is there a gauge that checks the concentricity of the 3 ID bores inside the bolt carrier? Although you did check the diameter of each there could still be an issue of concentricity to each other which could cause the bolt to bind. However, simply moving the bolt in and out of the carrier may be a sufficient check.
I feel like this channel is the 'geissele' of content. Moreso than geissele😂
Do a MIDWEST INDUSTRIES BCG!!!! They sell a ton of them.
How come you didn't mention Geissele using both the insert, and doughnut?
Would love to see a check on their new rifles which have had a lot of issues with machining and coating, to see if their internals function properly. Thanks for the great content Chad.
Why do you do the magnetic test?
I would love to see how well a geissele bolt would interface with a centurion sand cutter bolt carrier
Seems like Geissele bcg os slightly better than the sharps nickel boron bcg?
You mentioned that not having YFS fasterners for the gas key was a good thing in your opinion, can you explain that a little further please?
YFS screws are made in Taiwan. They are a lower cost option for screws (and tend to be lower quality). They have a tendency to break and/or come lose on a regular basis. Considering the forces and psi that the BCG has to contend with, lower quality is not what you want on a fighting rifle.
As stated above, yfs screws are low quality. They can shear right off the carrier. They're fine for handguards and such though. You'll find them on the budget of the budget bcgs. I saw a set on a Wilson Combat bcg and I was very disappointed
Where do u get these tools
Bill G eating a donut
“What!! Who let that machine mark go on that belly!”
Just subscribed. I need out to this kinda stuff lol did you go to school for this?
Colt extract spring with O-ring not overkill?
Did you say "Gold" spring?? I'm not gonna pretend like I know why that exists but I use to work in metal fab and I can without a doubt tell you a gold spring will not hold its resistance as long as even an aluminum spring... seems like a major gimic, can someone please explain?
Why do you prefer only having the spring on the ejector and not both? I have this exact same BCG, do you recommend that I remove the O ring?
What kind of problems does having a magnetic bolt cause? Just curious
If you shoot steel cased ammo, A LOT OF STEEL CLOGGING UP BCG.
@@NoWr2Run thank you,
What are your thoughts on McFarland gas rings?
What's the issue with the YFS fasteners? I've been watching your videos and I'm not sure why you keep mentioning those
My Heissele Super Duty Pistol hasn't been cycling properly lately. It will work fine right after cleaning for the first couple of mags, then I have to manually pull the charging handle back each time to eject the round to chamber the new one. Sometimes it will eject the old round but not chamber a new one.
Check gas block set screws, if that’s on right and straight then check the carrier key on your Bcg.. might have a loose carrier key screw.
Did you ever get your issue figured out? I noticed the comment was around a year ago
@@joshuabruce9920 no, i sold it for a huge loss...i regret that
@@rorothegoatboat Why the f**k didn't you send it to Geissele for inspection and repair??!?!
If you couldn't choose a DLC or NB coating for a BCG, what would the next best be?
I need to grab a couple of these next time they do a sale.
My 10.3 geiselle shoots so soft and almost no gas blowback. They really have it figured out
One of the worst things you can do to a bolt is HPT it. Terrible for the life of the bolt, but Geissele is using forgings for their bolts now, which should increase the strength considerably.
What carrier group brand do u prefer
Where do you get your BCG gauges?
In your cleaning tank I remember you saying that you used simple green precision and water. What ratio?
Where can I get an extractor groove gauge?
What bcg would you take Geissele ebcg vs sharps Bcg
Do you machine down the rear of your go/no go gauges so they don’t touch the ejector on the bolt face?
Great video, this was very informative and well made!
I’ve been searching for this bcg. The ones I’m finding don’t have the REBCG marking underneath the Geissele marking. Does anyone know why or seen the same? I don’t want to get a knock off or idk if the pic they are using is accurate.
They stopped labeling them with "rebcg" on the carrier . They now just say "geissele" . But it's the same carrier as this on the site now.
Very informative, thanks. Where can I find those testing tools?
Brownells is probably a safe bet
Where do you buy you're tolerance gages for bolt carrier groups for ar 15s
Great video man! where did you get all those gauges?
Between the Geissele rebcg and the LMT enhanced bcg which would you recommend and is there something you would recommend over either?
What are some of the issues that come up when parts do test positive for magnetism?
Steel case ammo sheds material and it can stick to components that have a magnetic charge.
I want one of those PTG Extractor Clearance guages. Don't like that it's over $100 tho bit very cool gauge
Even though all 5 of my ar rifles shoot flawlessly I really want to have them checked. Are these tools affordable for the non gunsmith guys?
Why would it matter if any of the parts were magnetic? Just curious cuz I truly don't know
Very impressive!! Subscribed!!
Wouldn't you want that firing pin channel to be tight tolerance even if youre design or not designing a precision gun??
I would love to see this test done on a Griffin armament bcg
Can you do one with the CMC enhanced BCG?
Where do you source your tools??
The recent REBCG that have come through my shop in complete uppers have different cam pins than this video.
not sure if you did any digging or not, but the standalone REBCGs are sold with a standard cam pin. however, the REBCGs that come in complete uppers have a proprietary directional cam pin and the Duty/Super Duty line of upper receivers are machined for the different cam pin
additionally, the directional cam pin will only function in a Super Duty upper. but any old BCG will also function perfectly fine in the SD upper receiver. the proprietary cam pin in the REBCG can be swapped out for a standard cam pin so that it will work in any milspec upper
What is the Magnetism about, cracks?
MPI or magnetic particle inspection causes the parts to become magnetized. They must be demagnetized or else will pick up trash and cause issues.
More specifically, if magnetic, then cleaning becomes a real problem because wear particles from the ferrous metal parts will stick to the magnetized parts. Even a full degreasing teardown may not entirely remove all the bits.
Why did Geisselle use the extractor spring donut AND the insert with a gold spring. Should've discarded the donut, just adds more pressure to the extractor.
GOSH DARN IT I LOVE THIS VIDEOS!!!
First for AR knowledge
Thank you, very helpful.