Shorter shells will work. On any barrel, the chamber length should be marked. If it says for 2 3/4" only, no 3" or 3.5". If it says 3", 2 3/4" shells will work also.
The big 3.5", same same.
In your Rossi, I vehemently recommend 2 3/4" LIGHT loads. The little singles like yours are very light, and mag loads will tear you a new one if your fit and form aren't up to par.
HTH....