I have an old glenfield model 75 and it jams after every shot with winchester whitebox ammmunition. I found some old hawthorne ammunition and shot it and it never jammed once. I shot it sideways and upside down and it performed flawlessly. I do not understand it. with the winchester it either catches on the old shell or edjects the old shell but the new shell doesnt go into the barrel. most of the time the winchester bullets hit around the barrel opening and get bent. what is causing this?