97's are very rugged machines but have a couple do weak places. The left hand extractor has a thin rib that guides the bolt in the receiver. If it is broken or worn off, the bolt wants to move too far to the right causing jams. Also, the sear notch on the hammer gets worn and/or full of dirt which can let the hammer follow the bolt home or cause a very light trigger pull, both of which are dangerous. Remember there is no manual safety, only the half cock on the hammer.
Have fun with your "new" shotgun. There is not another gun that sounds like a 97 being racked. More like a hay baler sound than a gun.