View Full Version : Bullet Button (Gen I?) in Aero Precision SPR-2 (.308)

11-05-2008, 12:28 AM
So I started to assemble my new Aero Precision SPR-2 .308 lower receiver tonight. First task was to install a bullet button. I had several (what are think are Gen I) that I purchased last year for various black rifle builds.

I installed the cage (the insert that needs to be driven in with a rubber mallet) without problems. When I test fitted the mag catch I found that it was binding up on the receiver where it recesses in to it. The dremel tool eventually solved that problem with a little grinding on the mag catch. Before I did that though I was experimenting with the mag catch from my Stag AR-15 LPK. While I've seen other posts in this forum that suggest the AR-15 mag catch works fine with the Bullet Button in an Armalite/Noveske/Aero lower, I found that the Armalite AR-10 magazine would only just barely catch on the AR-15 mag catch, and caught/latched much more reliably with the AR-10 mag catch. I also compared the two and also noticed that the protruding bit that sits in to the slot on the magazine was slightly longer on the AR-10 mag catch, than the AR-15 catch. Maybe .1" longer or so. Granted I never did install the BB spring and nut. I did these tests purely with finger pressure.

Anyway, I'd prefer to use the longer AR-10 mag catch for this build.

So I have two questions. Since the AR-10 mag catch bolt is longer than the AR-15's does this require a longer spring for use with the Gen I BB kit? Has anyone else successfully used an AR-15 mag catch with the BB in an AR-10 build?