I am a little nervous about posting a pic of the the pistol w/ SB15 arm brace on an open forum.
Here is what I did: Surplus Ammo and Arms Pistol marked stripped lower and Palmetto Pistol Build kit along with the Radical Firearms 300 8.5" complete upper. I used a Palmetto M16 BCG w/ 158 carpenter steal bolt I had in my spare parts bin. I will post up results when I test it. I am at the Buffalo Creek Shooting area almost every weekend if you want to try it out sometime before you commit.