SB15 Pistol build update

A while back we built an AR15 pistol up using an Aero Precision lower, DPMS complete upper from our friends at Brownells, and of course the Sig SB15 brace. Unfortunately, there were some feed issues with the gun, as demonstrated below:

After some testing, it was determined that the cause of the issue was likely the BCG. This was tested by putting the BCG in another gun and watching it double-feed like a champ all day long. So, the pistol has been upgraded. Here’s the new look, and new hotness.

SB15 with 40 round Pmag

Still the same handguard and fixed front sight post, but the bolt carrier group has been upgraded to a Colt 6920 BCG that was sitting around the office. The charging handle was upgraded to a Rainier Arms Raptor because of reasons, and then I stuck a 40 round PMag in it because reloading is stupid. It’s going to the range tomorrow to see how it works. Sharp eyed readers will also notice the Crimson Trace Railmaster Light/Laser combo mounted on the side of the gun, and there’s a good reason for that. This gun is actually a really neat platform for an HD gun, but to really fill that role properly it needs sweet beams. So we put the best laser on the market on it, because anything less than the best is a felony.

Of course, what it really needs to be perfect for HD is a suppressor. Luckily it’s already wearing an AAC flash hider, so now I just need to come up with 1,000 bucks and wait 9 months for the paperwork to get approved. Oh, and make sure the gun actually works.


  1. Ice is back with my brand new invention
    Something grabs a hold of me tightly
    Flow like a harpoon daily and nightly
    Will it ever stop? Yo – I don’t know
    Turn off the lights and I’ll glow

  2. For some reason the phrase “anything less than the best is a felony” in an article containing a DPMS product strikes me as ironic.

  3. So how big a difference is the arm brace vs a normal pistol buffer tube? I know it LOOKS more like a stock, but does it ACT more like a stock? It’s hollow in back, correct? What is it doing that the pistol buffer tube isn’t, other than looking a lot cooler? (Looking cool IS important, as we all know, but I’m really curious if it makes a significant difference.) 🙂

    1. KenL have you ever shouldered a SB15? If you have you wouldn’t have made a fool of yourself. The thing shoulders essentially like a normal stock and a heckuva lot better that a buffer tube.

      1. If I had shouldered one, I wouldn’t be ASKING THE QUESTION, would I? Did you get far enough in 3rd grade to learn what a question mark is? <<<That thing, right there, that's a question mark.

        Anyways, thanks for the info.

  4. Please do tell what brand and model of pistol tube you used. I’ve been looking for one that is short but still uses a castle nut. Thank you very much in advance.

  5. Good luck with the DPMS upper. I wouldn’t take one if it came for free. Seen way too many issues with their uppers and BCGs

    1. You’ll note that I have ditched the DPMS BCG in favor of a well used but always reliable Colt unit. Hopefully that will solve the double-feed problems I was having.

    2. I’ve never had an issue with a Pimped out Oracle Upper, I’ve had two of them, they run, Run and RUN!!

      Not saying you are wrong, You well know that these Manufacturers DO NOT make the parts they put in their Guns right?? They pretty much buy from the same sources!!

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