I also have a SA 20 Turkey Thug, with a 2 rd Choate extension. I dove me a bit crazy trying to get light target loads to get this gun to cycle.
I had read on another forum that is you polished the chamber all would be fine...not true
I polished my chamber, lubed my gun loaded it with some Win cheap shells, Bang, 1st one ejected right next to my foot, the nothing would cycle the gun.
I put some 3" mag shells and it threw them 25 yards away....
I had bought this gun for my daughter, for home defense, but ended up buying a youth 500. (She is just 5' tall) since this did not have my stamp of approval for a totally reliable gun.
We are going to Front Sight NV to do a 4 day shotgun course, so I went out to the range to check the zero on my Benelli. I also brought the SA 20 (as I really like that little gun with the ghost rings sighs and fiber optics). I had bought a case of Rio #3 buck, so for the heck of it, I shoved 5 shells into the SA 20. Ran perfect. I ended up going through a box of 25 just because I was so happy to see this gun run normal.
Tomorrow I will go and fids some 1 oz Win loads and runs 6 boxes through it to see if it breaks in right.
Tonight I tore it apart and spray it down with Gun Scrubber, then lubed it with break-free. (Not my favorite lube, but I want it to wear down any high spots, then I will give it a more "slippery" lube.
Need to shorten the stock by 1.5:so that midget daughter can shoot it. ( :? Guess this means I won't see much of it again, as daughter lives in Ft. Lauderdale, and I live in Washington. )