I have always used spp I have heard all the stories of the srp where they are harder, back in the day before Winchester changed the material in their cups we used to get a lot of primer flow. Now with the PF lowered That doen't happen any more. I don,t believe they burn that much more powder, And they cost more. As some of you have stated, you have to watch your main spring, so you can get a good strike when down to under 1.5# trigger pull. Put a limcat xl titanium pin in you gun use spp and forget about it
Ivan
SCS Vegas