Toughest BCG's in your opinion? 5.56/308

[DDadams]

Given the new "rules" the ATF has coming out with the possibility of serializing nearly every part of a rifle now - even RAILS - I'm wanting to stock up on a good few essentials before we have to pay transfers on every individual part ordered through a FFL.

I've really only ever bought complete rifles - and I'm not the most experienced with the parts in them anyways. We all start somewhere right?

So a major thing I want to know your opinions of is BCG's you'd buy if you were going to buy 10 or so spares for your 5.56 and .308 rifles.

I'm especially torn on coating/finishes. Everyone says NiB but then major players like kac don't even offer it and call it a BS option because of hydrogen embrittlement over time.


So nitride? DLC? Chrome? Some of everything? What would you do.

Anyone have a BCG they've had kick ass over 10k+ rounds and have no visible major wear they want to suggest?

I don't plan on NOT buying anything new again - but as most would likely agree, I'd rather not have the feds keeping a comprehensive list of every single part we buy for the obvious eventuality of it.

 

[55fairlane]

For what it's worth I have a couple chrome rock river arms (bought them at Camp perry) I feel there awesome, but good luck finding one

 

[Airtevron1]

possibility of serializing nearly every part of a rifle now - even RAILS

where did you hear this, link?

 

[mike4]

The US military has run more BCGs over 10K rounds than anyone else on the planet, so that is generally my guide. (You may lose a bolt lug within that round count, more likely with carbine length gas systems and shorter barrels and full auto.)

Phosphate finish, hard chrome interior. Exterior finish is less critical so long as you have reasonably smooth lubricated points of contact where it slides inside the upper receiver. Phosphate is a rougher finish as new than the others, but rapidly smooths out; it's long proven as a bolt carrier finish and I see no reason to deviate from the statistical confidence of that cumulative experience.

The bigger issue is the bolt carrier interior where the gas rings ride should be hard chromed, and I see it as stupid to deviate on that design element of the AR system unless it's just a "range toy" where the combination of reliability and durability are not considered a factor.

Some of the other coatings would be fine on the bolt carrier exterior, but as I understand it all of those from the most common aftermarket mfgs now use the same coating in the interior too, rather than proper hard chroming, except on their phosphate carriers.

I've followed my own advice above for 30 some years, but have not bought any BCGs recently to speak of since a complete BCM BCG 3 years ago, and a bolt supplied by Noveske along with a barrel last summer.

I see a lot of BCGs advertised with the bolt carrier and bolt steel types listed, so I would use that as a guide esp. on the bolt. If you are looking to economize, you could buy a number of complete BCGs where the specs look decent at lower cost, and then lay in a couple/few spare bolts from BCM, which has been my default source for bolts when I don't want to roll the dice on quality. You might also stock a spare gas key with screws, firing pin, firing pin retainers (in case of loss) and a few cam pins. I would completely avoid NiB on bolts for the reason you cite.

 

[DDadams]

possibility of serializing nearly every part of a rifle now - even RAILS

where did you hear this, link?

Summary of Final Rule 2021R-05F | Bureau of Alcohol, Tobacco, Firearms and Explosives

Definition of “Frame or Receiver” and Identification of Firearms On April 11, 2022, the Attorney General signed ATF final rule, Definition of “Frame or Receiver” and Identification of Firearms, amending ATF’s regulations by removing and replacing the regulatory definitions of “firearm frame or...

www.atf.gov

 

[DDadams]

The US military has run more BCGs over 10K rounds than anyone else on the planet, so that is generally my guide. (You may lose a bolt lug within that round count, more likely with carbine length gas systems and shorter barrels and full auto.)

Phosphate finish, hard chrome interior. Exterior finish is less critical so long as you have reasonably smooth lubricated points of contact where it slides inside the upper receiver. Phosphate is a rougher finish as new than the others, but rapidly smooths out; it's long proven as a bolt carrier finish and I see no reason to deviate from the statistical confidence of that cumulative experience.

The bigger issue is the bolt carrier interior where the gas rings ride should be hard chromed, and I see it as stupid to deviate on that design element of the AR system unless it's just a "range toy" where the combination of reliability and durability are not considered a factor.

Some of the other coatings would be fine on the bolt carrier exterior, but as I understand it all of those from the most common aftermarket mfgs now use the same coating in the interior too, rather than proper hard chroming, except on their phosphate carriers.

I've followed my own advice above for 30 some years, but have not bought any BCGs recently to speak of since a complete BCM BCG 3 years ago, and a bolt supplied by Noveske along with a barrel last summer.

I see a lot of BCGs advertised with the bolt carrier and bolt steel types listed, so I would use that as a guide esp. on the bolt. If you are looking to economize, you could buy a number of complete BCGs where the specs look decent at lower cost, and then lay in a couple/few spare bolts from BCM, which has been my default source for bolts when I don't want to roll the dice on quality. You might also stock a spare gas key with screws, firing pin, firing pin retainers (in case of loss) and a few cam pins. I would completely avoid NiB on bolts for the reason you cite.

Thank you so much for that post.

I saw TONS of great reviews on Toolcrafts BCGs and they're very economically priced.

PLUS there were multiple sites saying exactly what you said and to go with their phosphate bcg because it's chrome lined in those spots.

So that solves the bulk of it I think.

I'll probably buy a good few of those and get a few others just to see what the fuss is about. Like the APF SP4 coated bcg. Several reviewers calling it one of the best they've ever tried and the coating being incredible supposedly. But they're out of stock until sometime in May.

Edit:

For 'normal' mil-spec BCGs like toolcraft and others advertised as such rather than 'enhanced' or proprietary - would any extra parts likely be interchangeable? Firing pin, cam pins etc.


Edit2:

5.56 Bolt Carrier Group, Complete - Phosphate

* Will ship in frustration free packaging.

www.aeroprecisionusa.com

Looks like AP also offers phosphate + chrome lining. So I'll probably go with them actually as I don't think I've ever even seen a negative review on their quality for anything at all

 

[mike4]

Glad it was helpful. Just reading the tea leaves of incomplete data points online I would go with Toolcraft personally.

There is a lot of variation in 9mm bolts, and enough in .308 to create some troublesome compatibility concerns, but all the BCG parts are standard across 5.56mm as long you avoid "enhanced" variations as you noted.

 

[DadSmith]

AR10 (.308) BCG | FailZero BCGs

A completely assembled, ready to install .308 Bolt Carrier Group

www.failzero.com

AR15 Semi-Auto BCG | FailZero BCGs

A completely assembled, ready to install Semi-Auto Bolt Carrier Group

www.failzero.com

I've been using these. So far they have been excellent. Thousands of rounds fired and they are holding up great.

I'm not sure if the nib treatment makes the finish harder or not but it definitely makes it smoother.

Toolcraft has a DLC treated and Tin treated bcg I'd like to try sometime also.

 

[Ruger_Ronin]

+1 for Toolcraft NiB. It has performed flawless for me thus far. It is slick.

That said, I'm also a FailZero fan. Have great success with those as well.

 

[Kirk Freeman]

Toughest? Not sure what you mean. You need flex in it, thus C158 is milspec. I do like chrome for easier clean up and (slightly) better lubrication.

Before the world blew up I bought a bunch of BCGs from Monty. They are saltier now, but at least he has them.

Bolt Carrier Group

Centurion's bolt carrier group was created with HP/MPI tested bolts, heat-treated, and machined to give you the ultimate confidence in your weapon system.

centurionarms.com

 

[indysims]

The opinion of some people I trust suggest sticking to phosphate finish, hard chrome interior. The phosphate is somewhat porous and holds onto lube, resulting in a better performance than nickel boron or nitride

 

[Creedmoor]

Toughest? Not sure what you mean. You need flex in it, thus C158 is milspec. I do like chrome for easier clean up and (slightly) better lubrication.

Before the world blew up I bought a bunch of BCGs from Monty. They are saltier now, but at least he has them.

Bolt Carrier Group

Centurion's bolt carrier group was created with HP/MPI tested bolts, heat-treated, and machined to give you the ultimate confidence in your weapon system.

centurionarms.com

Why do you believe chrome has better lubrication?

 

[Kirk Freeman]

Why do you believe chrome has better lubrication?

Well, it DOES depend on the type of chrome, but right now, I would say:

1. NASA's research (well, LRC in Cleveland for NASA).
2. My brother, the Man of Steel, who runs a steel plant for AIT in PA.
3. Eugene Stoner.

But, if your objection is based on "distinction without difference" especially for Title I guns, then it is likely valid.

I mean the greatest AR makers in the world at Colt don't use chrome, so . . . why should any of us?

 

[JEBland]

I mean the greatest AR makers in the world at Colt don't use chrome, so . . . why should any of us?

Because Chris Bartocci said it's the best?

 

[BR8818]

I like the Micro Best hard chrome bcg. I shoot suppressed 90% of the time so it gets extra dirty, and still it just wipes right off. I also have a Young Manufacturing hard chrome bcg it's worked fine for over 4k now, but I don't like that they refuse to stake the carrier key bolts. Also the Young's are never in stock and overpriced in my opinion.

I bought all my MB bcg from PK Firearms. Micro Best makes alot of different OEM's bcgs they also make Primaryarms' house brand bcg you can usually pick those up for around a $100.

 

[Fordtough25]

I would think any mil spec BCG that has good staking and such would be an excellent back up, Colt, Rock river, spikes, Toolcraft.

 

[Refrigerator27]

BCM bcg's run really well for me but are pricy. I have no experience with toolcraft but I hear they are the same quality.

Aero BCG's have run flawlessly in my 6.5 Creedmoor build.

I ran a Palmetto Nitride BCG decently hard (3k-4k rounds) and have only had to replace the o-rings (which is an easy fix). IMO they shouldn't fail that early.

I had a .308 Bear Creek Arsenal Phosphate BCG that I got in a trade and that thing was a POS, jammed often, difficult to clean, and pins broke.

 

[bwframe]

... I ran a Palmetto Nitride BCG decently hard (3k-4k rounds) and have only had to replace the o-rings (which is an easy fix). IMO they shouldn't fail that early...

We used to hear a lot of trash talk about Palmetto BCG's. Not so much anymore?

Where did you buy your o-rings? Are there are other BCG parts we should keep on hand for in case?


.

 

[Kirk Freeman]

Because Chris Bartocci said it's the best?

I thought he liked Monty's? That's why I bought all them.

 

[JEBland]

I thought he liked Monty's? That's why I bought all them.

I recall in one video that he said he sends his BCGs out for chrome plating. He might buy the sweet, sweet Centurion Arms BCGs then have them plated. I've watched a fair bit of SmallArmsSolutions videos, but can try to look for it if of interest. (Links for others, not you; I know you know where to find those.)