Had problems with Federal 555 bulk pack in my GSG 1911, lots of Fail to Fire, Fail to Feed, and Fail to Eject, some of it is needed the new updated parts, some of it appears to be ammo.
Grabbed one box (50) of Federal Spitfires, had 2 Fail to Feed, 2 FTE
Grabbed one box (50) of Remington Yellowjackets, 1 Fail to Feed, first round, could be the flatter nose? I also have the older design mag followers still.
That reminds me, need to call ATI and get updated parts...
I've had very little problem with this ammo. Based on what you have said have the same problem with different batches of ammo out of different guns sounds like maybe a moisture problem? Any chance it got wet somehow?