Building an AR 15 input please

[Grizzman]

Are you sure the FSB is riveted in place? I've got two PSA uppers with standard FSB/gas blocks, and they've got the correct pins.

I'll be removing one of the FSBs this week.

Here's a bit of info from someone that knows a thing or two on the subject.

http://www.ar15.com/forums/t_2_138/1...aper_Pins.html