Pawn shop down the road has a 3 1/2 inch chambered 870 Express (Super Mag)in 85% or better condition for $165. Wasn't looking for an3 1/2 inch though---I only plan to shoot 2 3/4 inch. Didn't say OK because I wanted to research the pros and cons of the longer chamber with the shorter rounds. Am I risking failures to feed with the longer chamber and 2 3/4 inch?