A:
Not sure about a Rossi single shot specifically, but I used it with my ruger 10/22, pretty much a youth sized gun, and the process went very smooth. The only downfall to shooting a single shot gun on this rest is that if it's a break action, you have to un-velcro the barrel from the forearm rest between shots to open the breech and reload... Not terrible, but not as easy as a semi-auto or bolt action.