Picking a bolt carrier group can seem like a challenge. It often seems like there’s an insurmountable number of available options. However, when you break it down, it really isn’t as complicated as you think. There are only a few factors that really warrant consideration, and in the end, it mostly comes down to your own preference on profiles, materials and finishes in relation to your budget, and assurance that quality control isn’t slipping.
In this article, we’ll go over what to look for in a bolt carrier group, and then list a few of the very best.
Quick Buyer’s Guide
Profiles are the first consideration. For most people, there will be little practical difference aside from cost. A full-auto profile will cost you more than semi-auto. Generally, a semi-auto profile works more than well enough. But there are situations in which you’d want a full-auto profile; namely, when you’re planning to fire your AR-15 in full auto. It really is a lot simpler than it seems when you’re trying to decide on a profile for the best AR-15 bolt carrier group.
The second thing you’ll want to consider is material. Your bolt carrier group is put through a lot of punishment, whether it be heat or stress. Heavier materials are going to weather that better and be more reliable, but lighter materials are going to be lighter and smoother. The material you choose will directly determine the weapon’s longevity and reliability.
If you’ve decided on a material and profile, the next consideration is the bolt carrier group’s finish and lining. These work to protect your bolt carrier group from scratches, corrosion, and abrasion, as well as making the surface smoother. Finishes and linings can directly affect reliability and can reduce the need for lubrication. However, higher-quality linings can get pricey.
That covers all of the physical aspects of your bolt carrier group, but there is one more consideration, and that’s inspection and testing. If your AR-15 bolt carrier group hasn’t passed magnetic particle inspecting or high-pressure testing, then it may not live up to its advertising.
There’s a lot more specific information on these considerations that you can and should look into before making a purchase decision, but this guide should serve as a general overview on what you should be looking out for.
The Best AR-15 Bolt Carrier Groups
With the above guide, and your intentions for the construction of your AR, you should now have a decent idea about what you’re after in general. So, let’s open the curtain and take a look at some of the best overall options.
Bravo Company Bolt Carrier Group
This bolt carrier group is not the fanciest. It’s not the toughest. It’s also not the sleekest. What is this AR-15 bolt carrier group? It’s mil-spec, through and through. The Bravo Company bolt carrier group features a Carpenter 158 steel bolt that’s fully tested and inspected, as well as shot-peened for maximum quality assurance. The carrier is built from high-quality 8620 steel, lined and finished with chrome and phosphate. Its gas key is lined with chrome as well, and all of the components are pulled together by grade 8 hardened fasteners.
This isn’t an expensive bolt carrier, but it has everything the average Joe needs for their AR-15. It’s held to a high standard of quality and isn’t eager to let you down. The biggest downside of this bolt carrier group is that it just isn’t anything special. It’s mil-spec to the core. Standardized, reliable, simple and rugged. It can handle abuse and can dish it out as well. If you don’t care for fancy alloys or platings, and you’re fine with straight mil-spec, then this bolt carrier group does exactly what it needs to, and it does it well.
Colt Bolt Carrier Group
Colt is what the US military uses. It’s as simple as that. You literally can’t get more mil-spec than the Colt bolt carrier group, because the Colt bolt carrier group is the military specification. This is the standard by which all others are judged, and there’s a good reason why it’s the standard. The carrier is made from standard 8620 steel, the bolt is made out of standard Carpenter 158, and it’s been run through the standard high-pressure test and magnetic particle inspection. This bolt carrier group isn’t just standard mil-spec; it’s the mil-spec standard.
Colt is a brand trusted by the US army to deliver high-quality bolt carrier groups built with high-quality materials. The main downside to the Colt is that it’s more expensive than your bog standard mil-spec-like bolt carrier group, and when it’s available, it tends to sell out quickly. This is the perfect bolt carrier group for someone who wants parts identical to what the US army uses. It’s a reliable premium product that’s been battle-proven time and time again.
Spike’s Tactical Nickel Boron Bolt Carrier Group
Spike’s Tactical offers something a bit different than standard mil-spec. Their volt carrier group provides some higher-end features without costing much more than mil-spec. The bolt is shot-peened, tested and inspected. It’s made from Carpenter 15 steel, and the carrier is 8620 steel. The lining of the gas key is made from chrome. The group’s coating is nickel boron, which provides something a bit slicker than standard phosphate or chrome. Everything is banded together using mil-spec grade 8 hardened fasteners.
Spike’s offers a higher-end option with a smooth, slick finish. It goes above and beyond mil-spec to offer something a bit different, for the AR-15 that likes to purr with just a little more grace and elegance, without coming off as pompous. Reviews consistently praise this piece, and Spike’s Tactical has made a name for themselves with their high standard of quality and somewhat more refined designs.
Young Manufacturing National Match Light Bolt Carrier Group
Next to Spike’s Tactical, Young Manufacturing is a bit pompous, but they’ve earned that honor. Young’s bolt carrier groups have become the envy of any AR-builder, and it’s not hard to see why. Their light bolt carrier group is used by a large number of competitive shooters for the simple reason that it’s among the absolute best. The carrier uses standard carrier and bolt materials, but its lining and finish are both chrome. Moreover, it’s designed to weigh in at only ten-and-a-half ounces which makes it, as the name suggests, rather light. The surface in front of the carrier is also designed for a tighter fit.
Overall, this leads to a lower amount of reciprocating mass, a lessened recoil, and strong, consistent lockup. The group is tested with high pressure, inspected with magnetic particles and shot-peened to ensure the high level of quality that Young is known for. However, this exceptional quality comes at a price, and, in this case, that price is money. This AR bolt carrier group is for those who will only settle for the absolute best. You could only get a higher quality if you requisitioned the ghost of Sam Colt to forge it himself.
Now, these options are the best overall for most AR-15’s bolt carrier groups, but that doesn’t mean one of them is the best for your AR in specific. These four options cover only a few bases, from reliable and affordable to strict mil-spec, and from affordable flashiness to a razor-sharp competitive edge. If you don’t find the perfect bolt carrier group in this short list, then it’s more than likely that it’s still out there, just waiting for you to find it. Whether you’re after lightweight alloys and smooth running or unparalleled durability and rugged grit, the variety of bolt carrier groups is wide.
Whether or not the perfect bolt carrier group is in this list, it’s important that you always take into account the different factors that make a bolt carrier group work, and what your AR is going to be built around. For example, a simple, cheap and rugged AR is going to have different needs than a high-end competition shooter or an elegant showboat gun.