The 4 Best Bolt Carrier Groups — AR 15 BCG, Nickel Boron BCG 2023

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Ahh, the bolt carrier group—one the surest ways to start an online argument about the AR 15 is to ask which is the best one. Pretty soon, in any BCG discussion, you’ll hear words like full auto and semi auto bolt carrier groups, shot peened, and all manner of technical minutia that are primarily marketing jargon and means little to the average shooter.

In fact, pretty much any AR 15 BCG sold today is built to stringent military grade specifications and when purchasing from a reputable source, there is no need to get hung up over small details. Given that, the right bolt carrier group becomes more a question of cost and high-end treatment (all the products below can be purchased from Brownells). So, without further ado . . .

Here are our recommendations for the 4 best bolt carrier groups on the market:

Brownells – Best Nickel Boron Bolt Carrier Group

Here is a contender in the best bolt carrier group for the money category. Brownells offers a top quality mil spec BCG for just over a Benjamin. Remember when I said that at some level picking the best BCG is really a matter of your budget, and if you want to buy above mil spec? This BCG is a prime example of a budget mil spec unit that will provide long service at an affordable cost.

Seriously, buy one or two extra of these when they are so affordable. If the past is any indicator, there will come another time when you won’t be able to find a BCG at any price. This is one of the best nickel boron BCG’s period.

Spikes Tactical NiB Bolt Carrier Group

Spikes Tactical has been building high quality BCG’s for quite some time, and there is no better time to buy one of their top-shelf nickel boron finished BCG’s like there is now. This absolute top of the line NiB BCG offers only the finest, most advanced construction money can buy.
Made above and beyond all standard specifications, this BCG is ideal for match grade guns, precision sniper rifles, or for that discerning gun owner who demands nothing less than the absolute best. Go ahead, buy one of these American made gems. You’ll be glad you did.

Bravo Company Black Nitride Bolt Carrier Group

An ideal BCG that ranks right in the middle between low cost budget BCG’s and more expensive fancy ones hand machined by monks somewhere in Tibet. Bravo Company is well known for top quality AR parts, and their mil-spec BCG is no exception.

Made from Carpenter 158 steel, these top notch BCG’s are test fired before being sold, adding to your assurance that you are buying a functional, quality product. I know it’s tempting to buy the cheap BCG; I’ve done it myself more than a few times. But it really doesn’t hurt to spend a little bit of extra money and buy something much nicer, like the Bravo Company BCG.

Brownells M16 5.56 Lightweight Bolt Carrier Group

If you are the type of guy who wants to tune your rifle to reach peak performance, then the Brownells lightweight bolt carrier group is for you. A lightweight bolt carrier group can do a lot when combined with the proper AR 15 parts including an adjustable gas block and lightweight buffer. A lightweight buffer not only reduces weight from your build but can help reduce recoil. The less gas used to cycle your weapon the less recoil you’ll feel overall. A lightweight BCG requires less gas, so you can adjust the adjustable gas block to tune out some gas.

This bolt from Brownells also comes in multiple finishes including nickel-boron, titanium nitride, or nitride. It weighs a mere 8.2 ounces and is compatible with the 5.56mm, .300 Blackout, .223 Rem, and .204 Ruger. Bar none, it’s one of the best bolt carrier groups on the market.

Bolt Carrier Groups – Lots and Lots of Buzzwords

In a market as competitive as the AR 15 BCG market, people look for ways to stand out from the crowd. High end BCG’s speak for themselves with recognizable brands (Bravo Company, Colt, etc …), and high end finishes like nickel boron coatings. But in the middle and bottom, there is a constant battle to claim the title of best AR 15 bolt carrier group, and it has created a whole language that you should understand, but not get too hung up over.

Mil Spec is just that. Minimal standards to meet military requirements. However, this is not always an indicator of extreme high quality. Remember, military parts are often supplied by the lowest bidder. It just means a part is at least good enough for certain military applications. It’s a good baseline to judge things by, though, and I’d never buy a BCG that wasn’t at least mil spec. But then you get into a bunch of other words, like shot peened and magnetic particle testing and full auto profile, and some of those are eyebrow raising to say the least.

Shot peening is simply a method of surface hardening steel by blasting it with round metal or ceramic shot to cold work the surface, and is a standard hardening method for the best AR bolt carrier groups. Magnetic particle testing involves passing an electrical current through the part and examining the magnetic field around it. Minor inconsistencies or flaws in the part can be observed in the shape of the magnetic field. This too is pretty standard on an AR BCG, and should be expected. Like shot peening, it has entered into the realm of marketing buzzwords because it sounds impressive and complicated.

Speaking of impressive and complicated and cool all at once, we have the legally questionable sounding “full auto bolt carrier group.” I’ll go so far as to say you cannot have the best BCG unless it is a full auto profile. The ATF has consistently stated that a full auto or M16 BCG is perfectly legal to use in an AR 15, so long as no other full auto parts (like the hammer, trigger or sear) or other parts that will make your AR operate in happy fun time mode are installed. The full auto BCG has more mass than an AR 15 BCG, and offers more consistent reliability and function in your rifle due to the greater weight.

At a minimum, when looking for the best bolt carrier group, get a phosphate finished mil spec full auto BCG. These are the base standard from which all others are built on. Prices are very low right now, and you can easily find a full BCG for not much money. If you want something better, there are many fine choices out there, and all will serve you well. Match your BCG to your budget and your need, and you’ll be perfectly happy.

  • Owner of, Boyd Smith is a major handgun enthusiast, and although he owns Glocks, he prefers the revolving wheel type. His go-to guns are a Smith & Wesson 642 Performance Center for carry and a Ruger GP100 in the nightstand biometric safe (he has kids). He loads both revolvers with old-school 148-grain Federal Gold Medal .38 wadcutters. It’s OK if you think he’s a wimp. Email him.

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