I still haven't taken the barrels to Proof so decided to do a quick primer test this morning. After going over the data above I settled on 69.5gr of US 869 and figured out that I can use my 300 WSM Redding Competition neck sizing die for the 6.5 PRC. I can use the Competition seater die too but the 147gr sticks a bit in the seater, I decided to neck size and trim some once fired brass and try Federal GM215M and CCI 250 primers. The CCI 250 primers offered more resistance when seating. Here are the two 5-shot groups. The ES for the Federal primers looks really good but I think there was a problem with the last CCI 250 load of the group. I didn't make a scope adjustment after the Federal group.
I think I have enough good results to see the potential in this build and now I need to wrap up a few things with the rifle and tighten up my handloads to get the ES numbers lower than they are. I like this load at 69.5gr and magnum primers. 2,950 fps is very respectable for a 24" barrel. I do need to check at least 0.3gr either side and maybe 0.5gr but the 70.0gr load looked good ... for three shots!
I'll be warm and fuzzy if 69.0gr and 70.0gr will put five shots into 0.5 moa or a little over.
Federal GM215M (FPS)
2949, 2944, 2948, 2941, 2957
CCI 250 (FPS)
2938, 2946, 2947, 2947, 2911
View attachment 969275