257 Roberts + P Brass

[Bingoc]

Has anyone had the experience using the 257 Roberts + P brass over the non +P brass? And what differences have you found between using it and the non +P brass. I know that the +P brass has a thicker wall than the non +P version and the published loads for the non +P have to be reduced when using the +P brass, but what is the real advantage? Is there a substantial increase in velocity or life of the brass or etc.

 

[Blacktailer]

I would like to see some replies on this also. I have both but since they are used in a WWII milsurp Mauser, I don't load to max pressures.

 

[budlight]

I bought a custom fluted 26 inch 257 Roberts AI ER Shaw. I never could find 257 brass online. So all of my loads were made with Starline 7 mm Mauser. hodgdon Hybird 100V is about the best power for speed and accuracy in 100 -120 grain

StaBALL 6.5 is just smoking for 80 grain varmint loading in excess of 3500 fps

but I can tell you that sorting the brass in 308 is a must because of the 3 grain volume difference between commercial and military. Like you look up a load for 308 win and you might even be 3 grains under the written max load and it will pop the primers if you used Lake city mil brass.

 

[Bingoc]

Thanks for the heads up and will not mix the brass and will made up a load for the +P brass