I have a Marlin 336 that JES rebored from 30-30 to 38-55, and have been playing with it some recently in the cowboy big bore silhouette matches. I haven't shot it too much yet but so far it really works well. When it's not too hot out I'll shoot it with black powder, KIK FFg 40.0gr. with a card wad on top and the Lee 250gr. bullet cast from air cooled wheelweights, sized .377, and lubed with Bullshop's NASA lube. But recently it's been too hot to shoot long strings of black powder ammo, so I made up a BP duplicate with 18gr. IMR 4198, a tuft of pillow stuffing, and the same Lee bullet sized to .372" and paper patched back up to .378".
Both these loads run right at 1250 fps, track to the sights I have on the rifle, and will shoot into coffee cup sized groups at 200M from the bench using the barrel sights. I really like the 38-55 for silhouette, very accurate, very little recoil, and not everybody has one. It's pretty entertaining shooting the rams with it, if I don't see dust fly I know it's a hit. But things don't happen very fast, you have to wait for it and eventually the ram falls over. The sound of the hit gets back to me before I see anything happen. It's never rung one but they sure don't go flying like being hit by a 45-70.
I haven't shot it with full pressure smokeless loads (I have a 375 Taylor for that) but have no doubt that paper patched bullet, cast from straight lead, over a case full of RE7 would put the stomp on anything I wanted to kill.