Some marlins have a cartridge guide spring above the chamber. Most of them I have found had this spring broken and the cartridge carrier bent to compensate. Broken firing pins can also be a problem. If its been dry fired you could have a ping where the firing pin has hit the chamber. As always if you can shoot it do so, if not check everything very closely or maybe even invest in some dummy rounds to at least see if it will cycle. What ever you do don't get impatient and settle for something that's marginal. There were millions of these guns sold so mint closet fresh guns are still available on the cheap if you keep your eyes out. Nice new bolt 22's can be bought for less then $200 so don't pay anything more then $125 for used one unless its something really special.
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