.22 LR was not designed for 200-300+ yard shooting, that does not mean that it can't be done... if you enjoy shooting at distance that is great. Steel gong shooting is efficient in that it is reactive and does not require resetting, but it is not the best way to gauge accuracy, at least in a finely tuned and measured sense... but if you normally hit an 8" gong twice out of ten shots, but improve to 8 out of ten shots, it is a clear indicator of improved accuracy... once you are at 10 out of 10 shots, you have to shoot further out or go to a smaller gong.
Personally, I don't enjoy Rimfire "group" shooting beyond 100 yards, but we do a fair bit of "fun" shooting at much longer distances on silhouettes, clays and eggs etc...
Clearly you are having fun on that gong, and with iron sights, that is good shooting. Keep ringing the bell!
P.S - OP, that is the same rifle that I zeroed for sniping "look-out" birds when hunting sharptail grouse last fall, I made head shots out to 115 yards on the look-outs and then when they were down, ran the dog on the grounded birds and wingshot them with a 20 gauge... my 453 Lux was scoped and zeroed with stadia lines for longer distances.