Video Transcript
What we're going to go over today is this 9" 300 Blackout BCM upper receiver group. Now, before we get into this, I do want to talk about what 300 blackout is and why you might want to buy a 300 Blackout in case you may not know. So, 300 Blackout is actually very, very similar to 5.56 in relation to a lot of different things. So, first thing I want to show you guys is the difference in rounds. I'll show you guys have an idea of how similar this round is, comparatively to 5.56. We'll get some close-up shots for you guys. But the round is actually basically the exact same size. In fact, it's the same size casing for majority of the casing. So, you can put 300 Blackout rounds in 5.56 mags and vice versa.
So, first disclaimer before we get into this, be careful when you buy a 300 Blackout that you don't mix your ammo's up because a 5.56 will chamber a 300 Blackout and you will probably ruin your gun and may cause serious injury. Now, 300 Blackout was not designed to replace 5.56. It wasn't even designed to compete against it. It was actually designed to replace PDW guns that are in the 9mm caliber. So, if you're looking at the differences in the size of rounds and you're thinking that you can just replace your 5.56 guns with them, that's not exactly the case. A 300 Blackout is good at some things and not so great at other things. One of which the thing that is very good at is being smaller than 5.56. So, 300 Blackout is not like 5.56 in regards to that it needs a ton of velocity in order for it to be terminally effective. So, what that means is that when it hits flesh, it hits a bad guy, it doesn't need a lot of velocity in order for the round to perform well. 300 Blackout's requires its mass just like any other 30 caliber round or any .308, any 7.62x39, anything like that.
The round on its mass more than its velocity in order to achieve good terminal ballistics. So, that's the first note I want to talk about with 300 Blackout besides the similarities with the ammunition in relation to 5.56 is that it can go much shorter than 5.56 and still be effective. So, that is going to be your first selling point is if you're looking for a smaller gun that you want to conceal in a backpack or just something you want a smaller gun just for your house or home defense or something like that, 300 Blackout is a good option.
Now, like I mentioned, it was intended to replace 9mm and not 5.56. So, 300 Blackout is much of a round when it comes to just stopping power and stuff like that compared to the 9mm. You're going to get a lot more energy out of the gun. When I say energy, just this amount of mass is going to fly a lot faster than what a 9mm can. For example, the most common rounds for 300 Blackout are going to be 110 grains and these are going to be supersonic. So, this means they are going to be loud when you shoot them.
Basically, they're going to fly past the speed of sound and then something that 300 Blackout does at 5.56 cannot do is shoot subsonic. Now, there are 5.56 subsonic rounds, but they don't cycle. There's not a single gun out there that will cycle them effectively unless you have a bolt-action gun. But subsonic rounds are generally in the 200 to 220 grain range. There's some that are a little bit lighter, a little bit heavier. But, like I said, these are subsonic. So, these are going to travel under the speed of sound. So, if you have a suppressor with this gun, you shoot subsonic, it's going to be like a paintball gun. It's going to be very, very quiet. So, that's another thing that 300 Blackout does very well. It should be able to shoot subsonic ammo.
In brief summary, real quick, if you're looking at possibly purchasing a 300 Blackout and you're kind of questioning why you might want that, well, first thing, like I said, is shorter barrel compared to 5.56. And if you're looking for something that can go subsonic, so you have a suppressor, 300 Blackout is going to be very effective. And if you're looking for something short, but it's a little bit more effective than a PDW, like a 9mm gun, like an MP5 or something like that, 300 Blackout is a good option. And in fact, that's what it is designed to do.
So, if you're familiar with our other upper receiver group options that we sell on our website, we do sell BCM's in 5.56. And we did curate the SKUs that we sell because BCM has a ton of different options. They have different barrel profiles, different rail lengths, different types of rails, from M-LOCK to Picatinny to the new radar rail. They have different upper receivers, and all of these parts can be intermixed, and what that gives you is a ton of different options. So, what we try to do is hone down those options into just a couple that make the choices a little bit easier for you guys, and in our opinion, pick out some of the better features between those options. So, what we have here is the 9" 300 Blackout. Now, BCM sells a 7.5"-and a 9", or 7" 300 Blackout, and we're choosing not to sell the 7" option because they are not able to shoot subsonic rounds effectively. So, 300 Blackout was originally designed to be shot out of a 9" barrel.
So, there is one big misconception about 300 Blackout, and that revolves around the 9-" barrel. So, 300 Blackout was designed for a 9" barrel specifically, and what people think is that if they have a 9" barrel, that they have the max possible velocity they can get out of a 300 Blackout cartridge with that 9" barrel, something to do with max powder burn. That's not the case at all.
If you get a 16", 20", a 30", 300 Blackout barrel, those barrels are going to have more velocity. The same thing applies for 300 Blackout's, comparatively, to any other round out there. So, your shorter 5.56 barrels have less velocity to your longer ones, has nothing to do with powder burn when it comes to velocity of the round. However, 9" is kind of that sweet spot for performance for both supersonic and subsonic rounds for a 300 Blackout, and it is definitely the most common barrel length out there. And it's also the barrel length that we have the most experience with.
If you guys are familiar with one of our most popular YouTube videos, "Quietest Gun I've Ever Shot," this was done by Lucas. This is the gun that he shot. This is a 9" BCM 300 Blackout. Now, this is a little bit different versus the one that we sell now, and that is mainly because this is just old. So, the differences are this is a standard BCM upper receiver, this is a KeyMod rail, and this is actually a fluted 9" 300 Blackout barrel that they do not make anymore. But Lucas has a ton of rounds on this. This gun is extremely, extremely reliable and shoots very well, and he has it set up with all of these doodads.
Getting into the specifics of this gun, this comes with a compensator from BCM. All BCM 300 Blackout uppers come with this, they don't really have another option, you can't sub it out for an A2 or anything like that, so that's why we have it. This guy is very, very loud and very, very spicy, so if you buy one of these uppers, I definitely recommend swapping this out, preferably to something that's going to be a suppressor host of some kind, because like I said, one of the main attraction points of 300 blackout is being able to shoot subsonic ammo, and you can't do that without a suppressor.
Should have mentioned that earlier. If you buy this, shoot subsonic ammo without a suppressor, it's probably not going to work. Going back from there, we have a 8" M-LOCK BCM rail, so like I said, BCM has KeyMod, M-lock, pickatinny, and the radar rail. Currently, we are selling just the M-lock if we bring on another rail.
Nothing changes about the upper receiver grip at all, except for just the mounting solutions with the rail, but the M-lLOCK is awesome because it's very thin, very light, and we like it quite a bit. The barrel itself, like I mentioned probably 30 times by now, is 9", but it is a continuous taper profile, and this is currently the only taper profile that BCM offers. It's magnesium phosphate finish, it's chrome-lined, so what that means is it's a very, very good barrel when it comes down to how it's manufactured. So it's essentially mil-spec as mil-spec can get for a 300 Blackout.
Moving back to the upper receiver, this is one of the things that we really, really like about BCM, and that is the Mark II upper receiver. So the MK2 upper receiver does a couple things different than a standard upper receiver that I think are definite improvements, and I think this is actually the best upper receiver on the market, and this is across and against all brands. So first and foremost, it pushes the four assist forward. This is a very nice thing to have, absolutely not needed. However, with an AMB charging handle, you can actually articulate the AMB charging handle with the four assist push forward, and when you have a four assist that's a standard receiver and it's pushed all the way back, it's actually kind of hard to grab the AMB charging handle, but with this, you have free rein, and especially if you're a lefty, this is very beneficial.
Now, the other big thing with the MK2 is how much more material that we have with the upper receiver itself. So this upper receiver is beeped up quite a bit. In theory, this just means that this upper receiver is going to last a much longer time, comparatively standard receivers. However, AR-15 receivers last basically forever. It's very, very rare you ever see one that's worn out and failed because of just a lot of use. So the last note with the upper receiver is the fact that it's thermal fit that's across the board with all BCM upper receivers. They are thermal fit, so that means when the barrel's put into the upper receiver, it has to be heated up, and that's just because of how tight the tolerance is, which is a good thing. Tight tolerances are good.
The last thing that we need to talk about is the bolt carrier. Obviously, it comes with a BCM bolt carrier. If you're unfamiliar with the reputation of BCM bolt carrier groups, just YouTube it. These things have been torture tested. They are the gold standard in the industry when it comes to bolt carrier groups. So there's nothing negative to say about these things. These have worked extremely well. They're the majority of the bolt carrier groups we have in the armory. So buy with confidence if you're getting a BCM bolt carrier.
The upper receiver group will come in a big cardboard box wrapped in plastic and some bubble wrap. And what you're going to notice in there besides some stickers is this little piece of pack of plastic that will come with a M-LOCK sling QD mount, some Allen keys to attach that, and then a polymer section of Picatinny, if you so wish.
So we're going to set this guy up now. Now, like I mentioned earlier, the biggest benefits of 300 Blackout is how much shorter this gun can get. So I'm going to set this gun up as an AR pistol, actually. So I'm going to have a folder on the gun. I'm going to have this set up so it's ready to go in a backpack, ready to go in my car. It can be used for home defense and it can be just kind of stored nice and small. So the parts I'm going to put on this gun for the optic, I'm going to do an Aimpoint duty RDS. So for a build like this, not a lot of real estate for backup iron sights or anything like that. So I'm going to want to pick a nice durable optic that has a good battery life that I don't have to turn on in case I need to grab this gun nice and quick.
So Aimpoint Dot sight is definitely a good option for that. Sigs are great. Even a couple holosuns out there. Maybe you're surprised I just said that. So we are called to obey the laws of the land. So I highly recommend you doing that or just SBRing this if you so wish. However, there are some benefits to pistol braces or AR pistols specifically that I would like to address. And it's kind of why I'm setting this gun up this way. And that is being able to travel with this freely. So this is considered a pistol. So I can conceal this just like I would my Glock 19 and my waistband.
So I can cross state lines, go to other states that I'm allowed to conceal carry with legally. And I can bring this with me just as so. If this is SBR, there's some other paperwork you got to do. And it's kind of annoying. But AR pistols are free, have much more freedom of movement compared to comparatively to SBRs. Now the other things I'm going to do, I need to add a charging handle. This upper shoe group does not come with one. So I'm going to do a Radian. Not a Nestee because I'm not suppressing this quite yet. And this has a LAW Folder. So this is my little law folder adapter.
The last thing I'm going to do is I'm actually going to do a MagPul Picatinny QD point for my sling. And I'm going to use the T.REX sling to go with this. And the reason why I'm doing this is because of how short this rail is. If I attach the standard M-LOCK QD that the upper receiver groups come with, the sling is going to be mounted pretty far forward. I'm just going to lose some real estate with my hand. So I'm going to do the Picatinny guy. So let's throw all this stuff on the gun and see what it looks like.
There we have it. This is our little 300 Blackout build. Again, this is designed to be a little AR pistol, not suppressed or anything like that. So the way the light is orientated is for a couple reasons. So this is in a place right where I can fit my hand on the rail, given the minimal real estate. And I have still a good firm grip on the gun and also I orientated on this side, one because I have a click cap.
I don't want to deal with wires if I don't have to. That's why I chose a click cap. But when I fold the gun, it's just some of the bulk is off to that side versus onto that side. Now given I've afforded this, it doesn't matter all that much, but if I can put some more bulk onto the side of the gun folds, why not? Now the last thing I want to note with a gun like this, especially if you're going to build this upper into something like this, a folding gun, something that's going to go in a bag, even if it doesn't fold, is the size of the pistol grip. So here on this lower, we have a Reptilla pistol grip. Now there's a bunch out here that are similar in size. You have the emissary development, BCM even makes a shorter one.
And what the purpose of this grip is, is that it actually is about the same size as the 20 round magazine. So if I have a small gun like this, I throw a 20 rounder in there. If I do a full size grip, the grip's actually longer than the magazine. Looks kind of weird for one, but two, that's just again, more of a snag hazard if you're put in a bag. Now you can do an A2 grip on this and the A2 grips actually line up with 20 round mags as well.
So if you don't want to do a Reptilia or one of these smaller grips that happen to cost a little bit more money than normal grips, you can do an A2 and you'll be good to go. So last thing I want to talk about here is just the size difference between an 11.5 suppressed 5.56 and this nine inch BCM. You can see the size difference is quite substantial. So this gun is much shorter. The reason why I mentioned an 11.5 specifically, one that's becoming the most common short 5.56 gun currently was 10.3 as people are now moving to 11.5s, but nine inch, 300 block outs, excuse me, actually seven and a half inch, 300 block outs shooting one tens are about the same when it comes to terminal ballistics as 11.5 shooting 77 grain OTMs.
So given the fact that it's a 9", I throw some good supers in there. So I'm gonna talk about this gun in theory, according to what the internets say and some people that have tested this, this gun will be more terminally ballistic than that 11.5 5.56. So just something to note there. So hope you guys got something out of this. If you guys have any questions regarding the BCM uppers that we sell, really any questions at all, whether what ammo you should use for this, what lowers you should use, how to set this up, really again, just any questions at all, go ahead and shoot us an email at team@trex-arms.com.