I have an early Cordoba and had no troble with it for several years, it would cycle any and all ammo from 7/8 oz skeet loads to 3" heavy goose loads untill I used some Kent Fasteel shells. Now the bolt will hang up or cloase very slow. I have checked for burrs, polished, cleaned everything including the recoil spring and plunger. The spring seems ok but I am wondering if that may be the cause. Any advice would be greatly appriciated.