I also have used many SRPs in loads for the 38 spl and 357 mag with
no problems. With heavy loads of slow burning powder in the 357 SRPs
show velocities that are comparable to SPMPs. With modest charges
of fast powder in 38 spl loads there is an increase of 5-10 fps over
SPPs, less than the normal variation between rounds. I had one FTF
with a SRP in a revolver but found that it was caused by a strain
screw that had backed out without my knowledge.