Bought the CZ 712 last week, did a light cleaning, and found it wouldn't cycle on birdshot, or even 00 buckshot. The only thing that would work was some HD stuff that included a slug and was quite hot.
So......Tore it down completely, used 0000 steel wool on all the internals. Everything. (Didn't have any red Scoth-brite)
Put Slide-Guide in the receiver grooves for the bolt, used plenty of Ballistol in the recoil tube and piston area. Left it wet.
It now cycles on everything, even light birdshot! Went through about 100 rounds this morning, not one feed issue, and I am very, very pleased!!
