I recently bought a golden boy in the .17, which is one of the most accurate open sights guns I've ever shot, but it has one problem. When going to put a new cartridge in the chamber, sometimes the old catridge sticks, and the ejection arm slips over the rim. I clean and oil the heck out of it, which helps a little bit, but even with a good oiling, it happens once every ten rounds or so. The ejection arm seems to be sharp and has no reason to slip... any ideas? Same problem?