I have remington STS hulls and RP12 wads along with #2 lead that I want to add buffer. Longshot powder and FED 209A primer for 1 1/2 load. I can't find data for this load, I can get another primer if need be.
Thanks

Check with Precision Reloading; there is data for a 1.5 oz buffered load in Tom Roster's book (though not with the rp12). Ballistic products also has buffered data.

I loaded quite a few loads with Roster's data and 1.5 oz of 4's, and got 90% patterns at 40 yards. Good stuff. HTH, Dutch.