Originally Posted by Mule Deer
Hawk1,

Actually, the .257 was capable of 3100-3200 with a 100-grain ever since the introduction of IMR4350 in 1940


We got these velocities with the cartridge back in the 1980's,and mostly used IMR4831 back then as I recall.We never had a problem.....




The 280 Remington is overbore.

The 7 Rem Mag is over bore.