You probably don't want to drive those soft lead SWCs very fast, or you'll encounter heavy bore leading. First & foremost, make sure the bullets are a good fit in the chamber throats. 7.5 grs Unique will get those 265s approaching 900 fps in a 4" bbl, and you should find that has plenty of snoose for your sporting needs. Remember, it's a Special, not a Magnum.
Shoot safe.

Larry