257 Roberts + P Brass

Bingoc

Well-Known Member
LRH Team Member
Joined
Nov 16, 2011
Messages
124
Location
Richland ,WA
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

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Joined
Sep 17, 2019
Messages
96
Location
AZ
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

Well-Known Member
Joined
Sep 30, 2004
Messages
1,184
Location
Nevada
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.
 
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