BCM Blackout

Hello! Im looking to build a BCM 300 Blackout with a 9 inch barrel. Will any BCM lower work?


Is this what you are looking at?




If so, any AR15 lower should work, regardless of brand. Complete BCM lowers seem hard to come by and stripped lowers are not available. Any lower that you use will need to have a pistol receiver extension on it to remain legal for normal use. Any carbine or rifle stock would turn it into a short barreled rifle and would require registration and a tax stamp to keep you out of jail.


I did find this, which would work for your stated preference.

I’m sure there are other options, but that was the first one that came up. I don’t know the company, so do your due diligence before you buy from them.


Another gotcha with pistol ARs: Don’t put a vertical foregrip on it. That makes it an AOW (Any Other Weapon) which also takes an unconstitutional registration and tax stamp like an SBR (Short Barreled Rifle). On the other hand, a handstop or angled foregrip is ok.


That’s a more basic lower for $200. I’ve heard of people looking askance at Palmetto, but I’ve also heard that their quality improved over the past five years. I have a couple of their lowers, and while they are barebones, they function perfectly for me.

If you get more expensive lower receivers, you can get various optional things (not all are present in the Aero Precision model above):

  • a flared magwell to funnel the mag into the gun for more reliable reloads
  • a trigger guard forged smoothly as part of the frame for less knuckle wear
  • extra cuts to lighten your gun, give it some artistic appeal, or allow easier access to the action to clear malfunctions
  • colors besides black
  • an upper tensioning screw to remove the tiny bit of wobble against the upper for a premium feel (I don’t care so much about this)
  • an integral folding buffer tube adapter, so that you can fold the gun to a smaller size (often this is a one-trick pony that sacrifices on other features, but it can save a little on weight and length versus a Law Tactical or Sylvan Arms folding adapter, as well as save you money overall. I haven’t gone this route because I want a flared magwell and one-piece trigger guard, and I couldn’t find anything that had all three.)
  • upgraded triggers preinstalled for lighter pull and less creep or special trigger shapes (but you can always replace the stock trigger yourself later on as your budget allows)
  • choice of grip (replaceable)
  • choice of brace (replaceable)

This stuff is a far cry from the M4 & standard m16 battle rifles I was issued. If I enjoyed shooting them more I could get more into it.

I built one and have a second upper in 300 BK. But seemed to loose interest after shooting a few 3 gun matches.


So get or build a 6.5 Grendel or 6mm ARC upper. Both rounds supersonic too 1000 yds and go shoot distance.
Those two calibers let me shoot right along side my 6.5 Creedmoor & 308 in a smaller lighter gun w/less recoil.


That may be a great idea. I will consider it. The suppressor I have is a .30 caliber so no problem there. I even changed out the stock flash suppressor on my M1A with an adapter and use it. I reload so it wouldn’t cost me a fortune.