I shoot benellis brilliant guns , I had a Benelli montefeltro 20 bore bought new , and it was very cartridge fussy went back to gmk twice but never was sorted , did not like hull ,eley or express cartridges , but worked faultlessly with cheddite , rc , fiocchi and Rottweil my advise is try some different brands and find one it likes ,when they work the Benelli 20s are sweet handling guns , funny really as the 12 bore montefeltro I have has never been cartridge fussy and gets cleaned very rarely find it works better dry not over oiled