Well, I've owned this AR for at least two years now. I have put enough rounds through it to know that it cycles without issue when shooting unsuppressed and in the unsuppressed mode. Using my friend's AAC suppressor, it cycled flawlessly in suppressed mode. Using it with my Surefire SOCOM556-rc suppressor in suppressed mode, the damn thing doesn't cycle and continually has FTEs and FTFs. It's not getting enough gas in this mode. Has anyone else heard of any issues with the Sig 516 and Surefire suppressors? I never have any issues with my 11.5" BCM upper and my Surefires, but that's a direct gas upper. I was quite pleased with the Sig up to this point, but it's not worth much to me if it doesn't work with a suppressor considering that's the whole reason I bought it. I have yet to contact Sig, but I was curious to see what y'all had to say. I appreciate any help or input.