Started with a .357 Ruger Blackhawk with a 5 1/2 in barrel and open sights. Works good out to 70 -75 yds. But I've moved up to a Super Blackhawk in .44 Mag with a 10 in barrel, also with open sights. Works better.
Next I'll try it with a .45 ACP Super. Ho ho.
Remember the importance of shot placement.