I've been doing some research because I'm building my first AR's next year. I want to know who you guys would rank as the top 5 best BCG's out there. I've thrown this topic out over at SnipersHide and the responses I've got have been:

1.) LMT
2.) JP
3.) Sionics
4.) RCA
5.) Toolcraft

Honorable mentions: LWRC, Lantac

So I come here to ask, from your experience, which brands make the best BCG? I'll be shooting both suppressed and unsuppressed in various-length rifles.

Best?

LMT Enhanced Bolt in a Sandcutter carrier, in my opinion.

Is that necessary?

No.

Get a Toolcraft, and if you shoot more than 20k rounds you're in the zone to warrant an LMT bolt. Anything else is Gucci or unnecessary, or both. Buuuut with a screen name like that you'll probably buy a Mystic Black from Cryptic Coatings.

LMT Enhanced bolt in mil-spec carrier with chromed internal bore along with Permatex sealed and staked non-MIM gas key.

Just get a bcm and not worry about it.

Is nothing but an opinion poll.  Everybody gots one.

Microbest should be on the list.

I’m sure I don’t own any of the best or boutique

3 DD
2 BCM
1 SOLGW

several PSAs

#3

TC did me wrong. Not sure I’d put them anywhere near the best. Probably better than some knock off house brand stuff.

You're the first BCM fan to reply. That's good to know that BCM is an option. Do they make their BCGs in-house?

So far, LMT and BCM are in the lead with two mentions.

Can anyone back up the SOLGW and DD suggestions? I don't have anything from either of these two so I will definitely check them out.

I thought Sionics and Toolcraft made the BCGs for almost every brand

No mention of the Geissele REBCG?

Sionics makes BCGs?  I highly doubt that.

Toolcraft (makes carriers)
Microbest
Azimuth (spelling?)
AO

Those are the four bigger BCG suppliers that I can think of offhand.

No, Microbest supplies Sionics. Sionics just does a np3 coating and a test fire.

It’s really #1 Microbest, #2 Centurion, LMT, Rubber City Armory, #3 DD and Toolcraft. Maybe AO and the other one too.

Everyone else pretty much gets theirs from them or contracts them to stamp a logo.

I've not yet heard Geissele in the same conversation as "Best BCGs" but they do make stellar products and may be worth checking out. Has it undergone extensive military trials? Just curious.

OP, buy a Microbest BCG and pick up a spare bolt, firing pin, extractor etc.

Spending a bunch of money for a fancy BCG for your first AR is dumb and most likely won't offer enough returns to justify the additional expense.

I have a couple of Sionics NP3 carriers with LMT enhanced bolts which are excellent. DD chrome BCG's, BCM and Geissele are some of my others that I trust.

I'm new to firearms and this will be my first time building an AR. I didn't know you could mix and match the BCG, bolt, firing pin, and extractor. That sounds like a great way to try out different combinations from different makes. I love that!

I’ve shot a lot of rounds with PSA, Anderson, Bear Creek, and just about every “cheap budget” BCG you can find, plus the good ones from Colt, Fail Zero, LMT and so on. I’ve seen absolutely no difference. I clean my guns after every range day, and they all work great.

Carriers don't matter much as long as the carrier key is installed and staked correctly. Bolts matter. I've broken a couple. One was Aero. The other was unknown cheap brand. I have yet to break an LMT, BCM, DD or Geissele. Not that they can't break, but I think they are less likely to. You could also stumble on to a cheapie bolt that lasts forever. I always try and run the best parts available when possible. It gives me a little peace of mind.

If they can make a quality 7.62x39 bolt, chances are the rest of the line up is solid.

My statement only holds up the way I wrote it.   It doesn’t say or mean if they make a suck ass 7.62x39 bolt then the rest of their bolts suck.  Or if they don’t make a 7.62x39 bolt, then they suck.

GOOGLE SEARCH LINK

Y/M  = Young Manufacturing

JP

LOL


No

Who makes most BCGs?

There are only a few and most here would balk if they knew who made theirs.

Cryptic Coatings

I'm a big BCM fan but the only BCG that I have seen fail in recent years is the gas key started leaking on one of their carriers.  It was on an 11.5" upper and was run hard.  The leak was enough to cause reliability issues.

I guess I need to pull up my YT video same BCG. No better than any other and look exactly like Toolcraft which look exactly like PSA. Imagine that.

Saved about 20 different companies websites over time that showed them as manufacturing carriers, bolts, or both. Not selling but manufacturing.

Share the list.

Probably not a good idea to share them in today's climate.

Just because they come from the same manufacturer doesn’t mean they are all equal. Case in point PSA Father’s of Freedom is Microbest same as SOLGW, SOLGW HPTs theirs PSA doesn’t.

This. Vendor spec requirements play a huge role.

Attached File

Does HPT increase or decrease the longevity of a bolt?

Neither. It's a QA check. Are you baiting or genuinely curious?

Just trying to see where your perspective is.

Correct, it does nothing and can potentially harm the bolt.  It overstressed the bolt for no reason and can set set it up to fail in the future.  See the bolt above that cracked at the cam pin hole, it got the full monty of testing and failed.  MPI is fine and doesn't potentially hurt the bolt like the HPT can.  

I used to think the only way to go was high end BCGs until the most expensive BCG I had, which I bought to be uber reliable ending up being the only one I have ever had fail.  

BTW, Toolcraft is owned by PSA and makes MOST of the BCGs you can buy.  Looking at the BCM BCG compared to a Toolcraft, all the dimensions are exactly the same.  I no longer have the BCM.  I have a cheap BCA BCG in a 6.5G that has about 1k rounds through it, with no problems.  It is cut differently from the Toolcraft and other common BCGs so it isn't made by Toolcraft.  


My point from experience is, high dollar BCGs don't perform better than mid cost version and many are the EXACT same product with different stamps.  You often are just paying for a cool label with getting NOTHING better.

Geissele's bolt carrier groups are something that Geissele has actually managed to not screw up the QC on.  But they're charging you $365 for that not screwed up QC.


.....

Doesn't matter who makes the best BCG if their customer service is shit. With that said, I'd go with DD any day of the week. Great product, even greater service.

Just like everything else, it depends on what you wanna do with it. Are you gonna shoot CMP? Are you trying to clone an obscure Vietnam era gun? Is it for 3 gun, or a Sunday plinker?

I've been happy with my Toolcraft BCG's I've used in many of my builds.  I haven't taken any into combat though FWIW.

I have not tried one yet, I’ve been on the fence as I see them for allot less in the EE, my question is regarding Geissele BCG’s is the coating “that” much better?

I concur. There is a school of thought that is taking over now that batch testing is all that is needed as far as HPT testing goes.

Think of it this way. HPT testing was started long before modern procedures of today,  where we can consistently produce the steels without voids at almost a 100% rate. At that time, you would have a much higher chance of having voids or grain structure inconsistent with the high pressure needs of the bolt. Therefore, they were proof tested with a 70,000psi proof load ( M197 ) or 75,000psi load. Normal load pressures would be 55,000-62,000psi for NATO ammo. If the part was not up to par, then the excess pressure testing load would cause it to start to fail, and if the naked eye couldn't see it, then the magnetic particle test would usually show it. The problem is that MPI will only show fractures that have reached the surface, as the metallic powder would be drawn into the fissure on the surface when the part was magnetized.

Now, if the part had a fissure under the surface, it went undetected even though it tested good and MPI showed it to be good.

So, that pressure test that exceeded the standard load by 10K to 15Kpsi, initiated a failure that may, or may not have been there.

How many of you that hand load would exceed the norms by 10-15K psi? Nobody would, because we all know that we will end up with a bolt with shattered lugs at best very soon, or even initially.

It is now known that many times even though a bolt passes the HPT proof load test, it may have started a fissure inside that bolt that would have never been there without that extra pressure. The bolt will fail earlier in those cases than if it had not been HPT tested because it was stressed beyond its design.

Not all bolts will have issues from it, most won't.

Now,though, in 2022, we can make the material for the bolts so consistently well, that we don't need to over stress the bolts, causing potential shortening of life to see if they are good or not. We need only to test a few from each run. That way we are not potentially causing a problem that wasn't there to begin with, and the bolts from a good batch will only have to see 55k-62k, maybe 64k on a hot hot day, and will have less stress on them, allowing them to have a longer life.

The LMT E bolt uses A100 steel, which is superior to all others.  Extractor is proprietary tho.

JP makes a great 9310 bolt, very well finished.

BCM, plain,  no frills, solid bcg.

BRT is next on my list to try, hp/mp tested c158 chromed bolt, chromed carrier. Reasonably priced around $200.

No need to overthink on this.  Most all things engineered are done so with a “safety factor” incorporated into the design.

Example:  a bridge that is rated for 80,000# isn’t going to collapse @80,001#.  It likely has a SF of 2.5.  That way in the event 2 trucks meet at the same time and are overloaded, the bridge will hold.

Many many firearms are proof tested much in the same manner as bolts are.

Don’t get lost in the weeds on this. Just buy a quality standard bolt group. Colt, LMT, BRT, DS Arms, BCM, Expo from Primary Arms, microbest.

I like LMT. Their standard bolt actually has some improvement over other manufacturers. It has an annular groove circumferentially around the bolt body at the junction with the rear of the lugs. It removes the 90 degree angle and resultant stress riser there. LMT also batch tests bolts, so you’re not getting the added stress of HPT’ing each bolt.

The best kind are the ones that work correctly..could have any label on it

Stress cracks from HPT don't usually start deep inside a bolt. They form at the surface, at stress high points, where the right angles focus the stresses.  This is why MPI testing after a HP test works. This is most important on plated bolts, which can become brittle if not heat treated correctly. If these bolts have internal flaws they will come to the surface if severe. If not, well who cares at that point?

HPT/MPI may well be "wear" but it is an insignificant amount. You will exceed the nominal bolt life for anyone concerned about ultimate life. Just get a new bolt after 5k rounds if you are so squeamish. Hell... get a new barrel too.

IMO the "best" bolt is a JP, but I value precision.

I keep hearing Microbest which is a good thing, I've got to check them out. I'm definitely getting a LMT for one or two LMT's and a JP for a few of my builds. I haven't heard of any of the others but I'll check them out. Thank you.

Newbie question, how does a JP bolt enhance precision? I'm definitely getting a JP bolt for my SPR/long-range build along with either a 18" Lilja or Shilen barrel.

I have four Sionics NP3 carrier groups.  I'd put them up against anything.