Okay, weird to me, maybe not to y'all...

I'm seeing this between every 5-9 rounds out of one of my carbines where I get a double feed into the chamber where the rifle is attempting to feed both the new round and the spent cartridge, rear first, into the chamber. This is happening with all types of ammo, from factory .223, my handloads to the hotter M193, M855 and IMI Razor core. Extraction from the chamber is 100 percent but even shooting single shots occasionally I'll find the spent cartridge laying rear end inside the lower, on the empty mag, rear end toward the chamber.

Ejector issue? Time for a new spring? That ejector spring roll pin's tiny...