Well, I just inherited a beautiful S&W Model 1000 20ga shotgun from my grandfather. It's a nice gun, but it has problems of misfiring or FTL. I cleaned the gun until it squeaks but it still has the problems. After doing some google searching I think I landed on the problem. It has been suggested on several forums that the gun was originally designed to be used with 3" shells, and not 2 3/4" shells, and that using 2 /34" shells in the gun causes the problems I am having because they do not have enough power. It has been suggested that a gunsmith can enlarge the gas port on the gun and solve this problem, but only one that really knows what they are doing. I live near Abilene and do not know of a single real gunsmith shop here. Does anyone know of good one in or around Abilene?

Don't know one there but Frank Smith near Stevenville would be one if he will work on it.

Trammel in Breckenridge is another good gunsmith.

Not sure if those guys would but both are good Smiths

Longacres is the best on shotguns in Abilene . They are slooooooow. Located on S Oak just north of court house

These people stock parts for your gun and can fix you up.

http://www.lsgmfg.com

That gun should be fine with standard loads, how does the piston shock absorber look? The turn into black goo over time and gum things up.

You are exactly right. I have never used a gas piston shotgun before and I don't know if they are all like this, but this on must be thoroughly cleaned after each use. After I posted this question, I decided to break the gun down and check it out. Sure enough there was black tar like goop in piston shock absorber. After a thorough cleaning, the gun work perfectly for about two boxes of shells before it started messing up. I opened it and it was all dirty again. I made a video about it showing how to clean the gun and explaining why it happens.