I bought this maybe 3 years ago or so; seemed like a nice little rifle. Had a lot of problems first trying to shoot some Remington Golden Bullet HP's; (-I've since been told about them) later tried CCI Mini Mag round nosed; worked much better - still some occasional stove piping, etc. Aside from breaking it in by shooting more with more quality ammo (I've probably put just under 150 rounds through it), I've heard you can file the edge around the barrel opening above the ramp a bit to make bullets hang up less. Is this a good idea - and if so, should I want to file the top edge of the opening more; or just file lightly around the whole opening? Thanks!