The .41s I carried were all revolvers and the ammo was STHP's at first, then lead handloads.

But I did qualify with my .41 mag Desert Eagle after I had a holster and mag pouch made for it, and I used full power handloads. The targets were stapled on old conveyor belting and there were paper plate sized holes shot through it at every shooting station. The muzzle blast was awesome, to everyone but the guy next to me, and on the fifth shot it ripped my target loose and blew it through the hole in the belting. I replaced the target and finished with a perfect score.