with duck season over, I had about half a dozen failure to feed events while in the field. SBE2, lefty, no mods, ejects the empty without issue and the new round comes out of the mag and hangs up in the carrier waiting for the bolt to close. I could push it closed but by that time the birds have long gone. is it the recoil spring? I had the issue with dirty gun and with clean and lubed gun. what does the little spring buried in the receiver end of the barrel do?