Anyone else have a problem with 16" AR carbines not functioning with 55gr ammo? I got a new to me used AR carbine that doesn't like to function 55gr M193 ammo. It seems to function M855 62gr ammo much better, and reliably. Is that just kind of the nature of the beast? I have a 20" rifle that eats M193 all day long, but the 16"... not so much. I fired 29rds thru a mag today (just cleaned the rifle on monday) and had 3 jams by the time it was done. I was firing Federal M193s. The other day I fired some ADCOM M855 ammo, and it fired without a hitch. Is this a common problem to the AR carbines, or am I just lucky? thanks!