My old hunting buddy who has passed on now used his 7400 for twenty years. He shot Winchester super X 150 grain Power points all the time. He bought them by the case to get the same lot numbers. That gun never jammed once and alway shot 1 1/2 of better groups. They are a fairly accurate gun as a rule. Have a gunsmith check it out and see if the action is operating right. How old is the gun? Some of the older ones developed a gas works problem that can,t be fixed. They can however be converted to a pump by Remington or approved gunsmiths. My nephew has one of those.