SP and SR primers can be considered as being interchangeable for handgun use. As mentioned, the SR (and SPM) primers have a thicker primer cup so it is possible that if your firing pin has minimal impact energy, you may get misfires. Load up at least 10 empty cases, and if all go Bang! in your gun, you are probably OK. No changes in load are needed. I have one 9mm pistol which is unreliable with ammo using SR primers, but every other pistol and revolver I have is 100% OK with them.