Crystal ball is in the shop again for a front end alignment. Your shotgun was made between 1939 and 1957, so while old, it is well within the period for modern ammo (avoid steel shot).
As said, we cannot diagnose anything at long range. Light exterior rust- light oil (Kroil is best, but use what you can) clean coarse cloth, wet with oil, let soak a couple of hours, then rub with clean cloth.
If you have doubts about safety, have a smith take a look. Be sure that you are using correct length shell- unless it is marked 3 inch, do NOT try to shoot 3 inch shells (even if they DO fit)
Depending on condition, that can be a $500 and up shotgun, but since you let it rust I can send you $50 and a shipping label.....