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Old February 12, 2019, 05:50 PM   #1
Geezerbiker
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AR15 bolt carrier group

Since I started my AR15 project I've been making a list of parts I want but some have me a bit baffled.

I see a lot of different bolt carrier groups with a wide difference in prices and finishes. Unfortunately I'm clueless about what brands and finishes are good quality and others not so much.

Could you guys enlighten me on this?

Tony
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Old February 12, 2019, 06:29 PM   #2
ed308
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Lots of good brands on the web. I’ve used Toolcraft and Aero mostly the last couple of years. No problems either. Recently read where a nitrate bolts can be a problem. So would avoid a bolt that’s nitride treated. Ok on the barrel and bolt carrier. But not the bolt.
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Old February 12, 2019, 07:20 PM   #3
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Hard to find junk BCGs these days. Even PSA ones (TC or otherwise) are gtg.
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Old February 12, 2019, 07:43 PM   #4
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Phosphate ones are just fine, just a little hard to clean (marginally, not so much it's a deal breaker). I've used a number of nitride ones and never had a problem with them, and I've used a couple of nickel boron ones, all with good success. Some guys have reported problems with nickel boron BCG, something about they're so slick that they cycle too fast or something like that, but I never experienced that.
So, Toolcraft is a good choice, they have a lifetime warranty and are easy to find (JoeBobsOutfitters, Toms Tactical). PSA Premium BCG's have been very reliable for me, I've never had a bad one. I think they're made by Toolcraft and one other manufacturer who also has a very good reputation. Sanders Armory sells a BCG that some have reported some staking issues with, but their nitride BCG don't have nitrided extractors, they claim it makes the extractor too brittle. Only BCG that I had problems with and had to send back was a Bear Creek Arsenal one.
HPT (high pressure tested) and MPI (mag particle inspected) are both very good things to find on your BCG, and those tend to be better quality.
PSA premium BCG's have both and are pretty nice. I have a Ballistic Advantage BCG that cost twice as much as my Toolcraft, but doesn't run any better or worse. AIM Surplus often has BCG sales, their EXO NiB is the onoe I used to buy and had good luck with. Don't get suckered into the whole " I need to buy the $200 BCG with the fancy logo on it" because wuite often they're made by one or two major manufacturers like Toolcraft, and you're just paying extra for the slick logo.
Full auto bolt carrier groups are very common and much preferred, mostly because they have more mass and help the rifle cycle reliably. If you get a lightened or lightweight BCG, be forewarned you may have cycling issues and you'll be experimenting with buffer weights and different buffer springs to get the gun to run right.
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Old February 12, 2019, 09:32 PM   #5
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I was looking at a nickel boron made by AR-Stoner on Midway it's on sale but I'm out of gun money right now.

I always thought one part from a machine-gun makes is enough to run afoul of the BATF. Am I misinformed? PSA has or at least had M16 BCG's on sale cheap a few days ago.

I'm planning on using a Wilson adjustable gas block to slow down the action a bit so I don't have to look in the next county for my brass. Let me know if this is a dumb idea...

Tony
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Old February 12, 2019, 09:40 PM   #6
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Someone here turned me onto Aero stuff and I've been very happy with their AR15 line that I own, have 4 of them, all nitride BCG's (would like to know what is wrong w/ nitride if anyone wants to elaborate on why you would want to avoid that in the bolt). I think literally I might have never seen a malfunction in any of them and I waste a lot of ammo.

I will say no matter what you buy, keep an eye out for sales - regularly Aero will do a 15% site wide or 20% off parts, etc.. etc.. PSA I believe is similar and has some really great deals. With Aero you can sign up for notifications and they will spam you daily/weekly with the sales they run (which isn't spam if you are waiting for a deal ). Good luck in your quest.
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Old February 12, 2019, 09:42 PM   #7
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Quote:
Originally Posted by GB
'm planning on using a Wilson adjustable gas block to slow down the action a bit so I don't have to look in the next county for my brass. Let me know if this is a dumb idea...
I don't think it's a dumb idea.
I horsed around with an adjustable gas block once. I found that there was a quarter turn between doesn't cycle at all and cycles as hard as adjusted all the way open. It still sits on a rifle, but is threadlocked open.

My reservation about a screw adjustable gas block is that it can drift out of adjustment.

A heavy buffer can't. It may also have the benefit of keeping the bolt locked a bit longer and less junk blowing back into the action, though I've never found that to be a problem itself. I have a rifle with a 7.3 ounce buffer (6 steel weights and 1 tungsten) with a bizarrely gentle recoil that cycles so gently I have one magazine that won't lock back the bolt after the last round.

For a carbine, you can buy H3 buffers (3 tungsten weights), buy a commercial buffer (3 steel weights) and buy separate tungsten weights to replace yourself, or buy a cheap steel buffer like the ones sold for 9mm carbines. The steel weighs as much as the more expensive H3, but will not have the deadblow hammer like attributes of the sliding weight system.
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Old February 12, 2019, 09:46 PM   #8
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Quote:
Originally Posted by Geezerbiker View Post
I was looking at a nickel boron made by AR-Stoner on Midway it's on sale but I'm out of gun money right now.

I always thought one part from a machine-gun makes is enough to run afoul of the BATF. Am I misinformed? PSA has or at least had M16 BCG's on sale cheap a few days ago.

I'm planning on using a Wilson adjustable gas block to slow down the action a bit so I don't have to look in the next county for my brass. Let me know if this is a dumb idea...

Tony
Nothing wrong with a "full auto BCG" - it just means it has some extra metal not carved away, it's the auto sear (and I think more specifically a drop in auto sear "DIAS") that they classified as a machine gun on it's own.. Maybe some other parts, maybe someone else can elaborate, but not the full auto style BCG, not that I'm recommending that or saying a semi auto style won't work famously...

I don't think I'll ever be that into tinkering with these things - for me I'd rather use known-to-work-together parts and have a good rifle versus Frankensteining .. but I will say I used a JP tuned spring and an H2 with really great results in one rifle that had a lot of twang to it. Better to start with a carbine buffer, make sure it all works, then start messing with stuff if you ask me.
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Old February 12, 2019, 09:50 PM   #9
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I bought a Trinity Force A2 stock and it came with a spring and buffer. I'll look into getting a heavier buffer later on.

PSA has full auto BCG's with a black nitrite finish on sale for 50 bucks. I'm having a tough time not putting one on my card right now...

Tony
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Old February 12, 2019, 11:05 PM   #10
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Using the full auto BCG is not a violation of any law, it just describes or designates the shape of the bolt carrier. I have one if the $50 PSA bug's that are on sale right now. Not as nicely finished as their premium one, but seems to function fine, staking on mine looks good.
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Old February 12, 2019, 11:08 PM   #11
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Also, if you want to get some of the twang out of the buffer tube, look into a Tubbs buffer spring, or the almost as good and far less expensive strike industries flat wound buffer spring.
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Old February 13, 2019, 07:46 AM   #12
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I have BCG's from 10-12 manufacturers of several surface treatments. I like the NiB for suppressor use as they clean up easier than phos coated(look nicer, too). Brownells phosphate coated BCG seem to be a bit smoother than some others. PSA nitiride is a nice smooth slick finish. ARE(?) NiB is a winner. Adams Arms piston bolt carriers have a dandy nitiride(?) finish that doesn't carbon up. I may have a couple of BCA and if so, those seemed to be a bit coarse.
Not many "bad" BCG on the market now although things like improper key staking may show up here and there. That's a bigger issue for me than external finish.
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Old February 13, 2019, 11:50 AM   #13
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I've used six different brands.
Other than differences in ease of cleaning and a couple rough (and cheap!) phosphated carriers requiring some 'break-in' time, there was no notable difference ... except one.

The one exception is my nickel boron YM National Match (side-charging version) BCG.
That nickel boron is awesome. No scrubbing. No soaking in chemicals. All I have to do to clean that BCG is pull it apart, wipe it with a rag - and maybe poke a couple places with cotton swabs - and it's good to go. (But it did cost me $380!)

Best bang for your buck right now...?
Probably one of the black nitrided BCGs engraved with the company's logo. (Vague, I know. But...)
They seem to almost all be made by the same company, and rebranded for the reseller - of which, there are dozens.
Nearly all of the bolt carriers are paired with good bolts, and the nitride does make cleaning a bit easier. Should be plenty good.

Keep your eyes on the usual websites, plus gun.deals.com*, for a good deal. In any given week, there's usually at least one shop offering the black nitride BCGs for $50 - often with free shipping, too(!). (Which is awesome. I paid notably more for just a bolt 5 years ago. Complete BCGs were generally $130 at the low end, on up to $300-400 for something with a reputable name brand.)


*Formerly slickguns.
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Last edited by FrankenMauser; February 13, 2019 at 12:02 PM. Reason: Changed referral. Company changed names.
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Old February 13, 2019, 08:30 PM   #14
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Thanks guys for enlightening me on this. I now feel seriously less intimated when selecting parts for this project. I should have the bux for the BCG next month and I'll one piece at a time it after that until around August or September when I have it scheduled to complete it.

I have 2 other gun project that need money this year. I can let one slide but I have a varmint rifle out with a gunsmith that will need about 500 bux to complete and I can't let this one slide...

Tony
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Old February 13, 2019, 09:58 PM   #15
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Tool Craft is known to be a high quality maker of BCGs. I believe they make PSAs Premium line. I have a couple of those and they have been great. Also, I really like the Black Nitride BCG from Aim Surplus. Another favorite of mine, and the most expensive, is from Sharps Rifle Company.
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Old February 13, 2019, 11:47 PM   #16
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Also, if you want to get some of the twang out of the buffer tube ...
There is also a kit from Izhmash that takes care of this.
JK ; --) no flames
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Old February 14, 2019, 04:44 PM   #17
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Quote:
Originally Posted by Geezerbiker View Post
I bought a Trinity Force A2 stock and it came with a spring and buffer. I'll look into getting a heavier buffer later on.

PSA has full auto BCG's with a black nitrite finish on sale for 50 bucks. I'm having a tough time not putting one on my card right now...

Tony


Those are a great deal at that price. I just bought one myself as a backup BCG spare parts... I mean, actually an another unfinished rifle starting as a spare part.


Andrew - Lancaster, CA
NRA Life Member, Calguns.net contributor, CGF / SAF / CRPA / FPC / NAGR / NRA-ILA contributor, USCCA member
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Old February 14, 2019, 04:45 PM   #18
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AR15 bolt carrier group

Quote:
Originally Posted by Bozz10mm View Post
Tool Craft is known to be a high quality maker of BCGs. I believe they make PSAs Premium line. I have a couple of those and they have been great. Also, I really like the Black Nitride BCG from Aim Surplus. Another favorite of mine, and the most expensive, is from Sharps Rifle Company.


The dirty secret out there is Toolcraft makes MOST of everyone’s BCG people just don’t know it (rebranded). There are few actual manufacturers, many rebrand and sell variations.


Andrew - Lancaster, CA
NRA Life Member, Calguns.net contributor, CGF / SAF / CRPA / FPC / NAGR / NRA-ILA contributor, USCCA member

Last edited by lordmorgul; February 16, 2019 at 04:10 AM.
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Old February 14, 2019, 07:01 PM   #19
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Here is a good deal from PSA.
https://palmettostatearmory.com/psa-...516446953.html
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Old February 15, 2019, 02:34 AM   #20
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Geezerbiker- Just a tip on taming down the wild brass flinging... I don't have any experience with adjustable gas blocks- always been an answer to a question I never personally asked kinda problem. However, what a lot of folks overlook is the ejector spring.

Purchase one or two extra ejector springs. Clip a coil or two off until the top 1/4 of the ejector remains above the top rim of the bolt. You can continue to clip and tune until the top of the ejector is flush with the top of the bolt rim. It's just a matter of trimming to your taste.
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Old February 15, 2019, 07:25 AM   #21
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"I don't have any experience with adjustable gas blocks- always been an answer to a question I never personally asked kinda problem."

That's odd. An adjustable gas block has been at least a viable answer to nearly every DI problem I've encountered. On the other hand, up till now, I've never really considered that "trimming" the ejector spring would solve anything.
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Old February 16, 2019, 01:47 AM   #22
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I said "a question I never personally asked." From my limited experience with them, it seems to be a headache I don't care to deal with. Any problems I've had that could probably be solved with an adjustable gas block, I've managed to cure with buffer weights, springs, enlarging undersized barrel gas holes. A lot of folks seem to really like adjustable gas blocks, but there have been quite a few times I've heard folks say they don't stay adjusted or whatever. I just don't want that headache and have never had the need to get one. I haven't put out a rifle upper yet (32 so far) that has needed one.
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Old February 16, 2019, 03:29 AM   #23
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There are several adjustable gas blocks on the market. Do you know if these guys were using a particular brand? I plan to go with a Wilson because I've had such good luck with their M1911 parts...

Tony
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Old February 16, 2019, 03:44 AM   #24
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Don't buy a lightweight bcg.

Don't buy a lightweight BCG.

DON'T BUY A LIGHTWEIGHT BCG!
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Old February 16, 2019, 03:50 AM   #25
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Quote:
Originally Posted by riffraff View Post
Nothing wrong with a "full auto BCG" - it just means it has some extra metal not carved away, it's the auto sear (and I think more specifically a drop in auto sear "DIAS") that they classified as a machine gun on it's own.. Maybe some other parts, maybe someone else can elaborate, but not the full auto style BCG, not that I'm recommending that or saying a semi auto style won't work famously...

I don't think I'll ever be that into tinkering with these things - for me I'd rather use known-to-work-together parts and have a good rifle versus Frankensteining .. but I will say I used a JP tuned spring and an H2 with really great results in one rifle that had a lot of twang to it. Better to start with a carbine buffer, make sure it all works, then start messing with stuff if you ask me.
On the topic of full auto rated BCG's and drop in auto sears, those drop in sears are stupid easy to make, literally any 15 year old shop student in high school with the prints could make them. As time goes on tho and 3D printing becomes more popular, drop in sears and the selector switches are going to be accessible by anyone. Full auto BCG's are precision made and would be difficult for 3D printers to make correctly, so I think in the future, if AR's aren't banned by then, there's going to be a push to stop full auto rated BCG's to civilians.

More likely AR's will just be folded into the "machine gun" NFA category under the constructive possession argument.
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