This thread has been very helpful! I inherited my Uncle's Sprtsman 58 12 ga. back in the 1980s. I took it dove and quail hunting a few times but it jammed frequently, so I put it in the safe and forgot about it. I got it out recently and decided to get it up and running. I took it apart to clean it, and it was filthy....I mean really filthy. The barrel dates this one to Jan. 1958....I think my Uncle bought it new....I am not sure he ever cleaned it. The holes in the cap were pretty much sealed up with grime, and the piston and ring was all gunked up. The gas tube itself was pretty clean - I just cleaned it with a soft cloth. I noticed the bolt wouldn't stay open, and from this thread learned that the tab on the carrier group was broken off....a new carrier group is on order from Numrich. Also ordered a new receiver buffer. Mine has the dreaded crack in the receiver...but it is small enough (about 1/16") that I will keep a close eye on it. If it gets any bigger I will have it milled out. I am anxious to get this thing out and run a few rounds through it!