AR Sponsor
Posted: 5/7/2012 8:18:58 AM EDT
| I am working on putting together a SBR. I told my gunsmith that I wanted Bushmaster lower, upper, and barrel. The stamp on the upper is different than the one on the lower. The lower is stamped with a keyhole. The upper is stamped with a box or a square. If anyone can tell me what brand the upper is, I would greatly appreciate it. |
| The marks you are describing are the forging marks. Multiple manufacturers get their uppers and lowers from the same places foundries. It is the machening they do that makes them their own. You would need to try and find another mark to find out who's brand it is. |
AR Sponsor