I hunt with an old savage 20ga, it's a 3" gun and choked xtra full at .585
with 3" lead shot 35yds was about the limit.
I called savage and federal and both said it was safe to shoot the Fed HVWT shells with the flight control wads in this gun. It patterns both 3"#7 and #6HVWT very well.
Have shot 2 3/4" TSS reloads in it for several seasons both #9 and #8 shot and patterns both very good.
have not had any scratches, scours or damage to the bore or choke, still measures .585 after many shots.
If it was mine and it's a safe gun to shoot modern lead out of it I would shoot TSS out of it.