I got a m-90 20ga for xmas, the problem is about every 4th shot the shell wont come out of the tube all the way, so it wont feed into the barrel. And loading the gun, it takes alot of pressure to get the base of the shell into the tube. I've had an sbe for acouple of years and have not had any trouble with it. Has anyone else had this same problem with their 20 gauge? if so what or how did you fix it?