Colt 38 Super with a BAR-STO Barrel and match trigger
First make sure the loads are powerful enough to cycle the action, but not so powerful as to blow out the case head. Most pistol have barrels which do not support the case head. Some "race guns" meant for competition were custom fitted by gunsmiths with barrels which fully support the camber and can with stand +P+ loads.
Second make sure the bullet neck tension is sufficient so the bullet does not set back in the loading process, i.e. moving from the magazine to the chamber. This can also cause the case head to blow out due to excessive pressure.
Same pistol with the slid locked to the rear.
Third, make sure the overall length of the loads is correct for the 38 Super. rounds which are too short may jam. Rounds to long won't fit into magazines, or cycle. Consult a good hand loading manual for the cartridge overall length.
Have fun, the 38 super is a great round and the Colt is a great gun.