I was looking around yesterday, and ran across these. They say they are safe for classic guns, but I dunno.... Sure seems pretty hot for a SxS that is almost 100 yrs old.... Says on side of box, for Modern or Classic guns.... I might shoot them out of my model 12, which is a 1946 gun..... But I'd think they have a pretty solid thump to them.
SPECS
Gauge: 12
Shell Length: 2 3/4"
Shot Weight: 1 1/4 oz
Muzzle Velocity: 1400 FPS
https://www.rogerssportinggoods.com/...oz-Case-of-250