This is confusing.

I've shot 300+ rounds of 225 gr Sirra ove 60 gr R-15 in the last ten years. I still have quite a bit of that lot of powder also.

I don't quite get 2600 fps out of my 22 in barrel.

I have used the same load with NPT and TBBC [20-30 rounds of each] all with no pressure signs. Still on the same 100 cases 30 that are still unused. These get around 2640fps or what I get with The TBBC factory load. I used the same load with 200 gr bulk Core-Lokts but they shoot so far away fro the 225's that I don't use them anymore either.

This 60 R15 was the max load in the Barnes manual for a 225 X bullet a few years ago before I quit on them.