The bolt carrier group (BCG) is the beating heart of an AR. Like our own heart, it is not only critical to making things function, but it is also put under significant stress to accomplish that. Sure there are many parts of an AR that are critical, most of them in fact. But the BCG is the workhorse – feeding rounds, firing rounds, and extracting rounds.
When I decided to build my “dream AR” (though I think we all have multiple dream ARs for different purposes), I wanted to go with bomb-proof parts I knew I could depend on. Sure, I knew I might have to sacrifice some weight here and there, but my goal was to make an ultra-reliable AR that, while it may not be the best at any one thing, still excelled at everything. What did I want then, in a BCG? Reliability and durability. If it had innovative features that contributed to those things, bonus. If it looked cool doing it? Yes please. Let’s face it – we all want things that work great, but if we had the choice between works great and looks okay, or works great AND looks awesome, looks awesome wins every time. Enter the Lantac® Enhanced BCG Full-Auto Style (Lantac® E-BCG®). All BCGs are not created equal. There are really five things to look at when it comes to choosing one: full-auto style, materials, coating, quality control, and let’s call the final category “extras.” Full-auto style is probably the simplest of them all. A full-auto carrier is slightly longer, heaver, and has a lug on the bottom, which (if we were lucky enough to have full-auto ARs) would contact the sear release when the bolt is locked and much fun is had by all. The full-auto BCG is pretty standard these days for most manufacturers. You add a little more weight, but you also add a little more strength and reliability. As the full name suggests, the Lantac® E-BCG® is full-auto. Materials are perhaps the most important of the five factors. Like the EDC knife in your pocket and a million other things, BCGs can be made from different things. Most BCGs are made from steel, but like BCGs themselves, not all steel is created equally. The carrier on the Lantac® E-BCG® is made from 8620 steel with a shot-peened bolt manufactured from Carpenter 158. We could go into the details of machinability, forming, heat treatment, etc. for these steels, but that’s for another post and someone with a hell of a lot more knowledge on the topic than me. Let’s just say these are excellent materials that will exceed our reliability and durability needs. Next up is coating. The coating on a BCG affects a few different things – durability and lubricity. The Lantac® E-BCG® is Electroless Nickel Boron (NiB) coated using their UCT EXO process, which from Lantac®’s website delivers “…extreme lubricity with a friction coefficient of .02 and a surface hardness of 82-85 Rockwell C.” What does THAT mean? It means it’s very hard, durable, and slick. Why does slick matter? First, because your BCG is flying back and forth with every round you fire, in significant contact with other parts of your AR. It’s also getting dirtier and dirtier with each of those rounds. That means you want something with very low friction. It also means all that carbon has a tougher time sticking to it which equals a gun that runs better and a BCG that’s easier to clean. How about quality control? There are two main things you want to look for here – testing and proper staking. Magnetic Particle Inspection (MPI) testing is basically a test using a magnetic field to detect inconsistencies in the physical structure of the bolt. If there are inconsistencies, that equals a weak point. Those don’t make it past quality control. You should be able to see “MPI” or “MP” stamped or engraved on the bolt. If you’re buying a BCG and don’t see that, check the website or call the company to enquire. The gas key is a separate piece of the carrier that’s bolted on with two fasteners (which are small bolts, but I’m going to call them fasteners so as not to cause confusion with the bolt). The last thing you want is for the gas key to come loose or detach from the carrier. To help ensure this, the fastener heads attaching the gas key are intentionally deformed so they won’t back out. Each fastener head should be staked twice and the deformation should cause sufficient material to cross over from carrier to fastener to keep the fastener from rotating. You also want to look for “Grade 8” fasteners which basically means “high strength.” The Lantac® E-BCG® is properly staked as well as MPI tested. And then there were extras and this BCG has them in spades. The carrier features unique shrouded, forward-facing gas ports to vent gas in a way that results in the gun running flatter, smoother, cooler and cleaner. The flared tail of the carrier creates a better lock position within the upper for more consistency and accuracy. One of my favorite features is the cam pin. It’s ultra-smooth and domed which reduces wear. At 11.7oz and retailing north of $270, this BCG is definitely not something you want in a lightweight or budget build. But if you want dependable, reliable, super slick, and full of small, but smart innovations (and did I mention it looks awesome), the Lantac® E-BCG® is the BCG your AR deserves.