That's good news, since I purchased 4 boxes of just that loading. I'm new to the .257 Bob & really am enjoying this rifle. I'll soon start reloading with the +P Hornady brass & see what this cartridge can really do. Thanks so much.
3D –
The answer is the Ruger action on your rifle is the same one they barrel for 52,000 CUP, 54,000 CUP and 63,000+ PSI loads. No need to worry about 50,000 CUP 2257 Roberts +P loads.
Congrats on your new rifle! Got mine (standard 22” M77R) a couple years ago and it has become my favorite bolt gun. Here’s what min does:
3609fps = 75g V-MAX and H4895
3163fps = 110g Accubond and H4350
2958fps = 115g TSX and H4831SC
3013fps = 115g TSX and H4350
2899fps = 120g Grand Slam and H4831SC
2904fps = 120g Partition and H4831SC
2947fps = 120g A-Frame and H4831SC
All loads with WW +P brass and CCI 250 primers.
Several weeks ago the 75g V-Max load put 3 shots into a group measuring 0.232” center-to-center at 100 yards. And a couple weeks ago I took a coyote with this load at 479 lasered yards. The Roberts has a lot of “can do”.
Have fun!