Hawk1,

Actually, the .257 was capable of 3100-3200 with a 100-grain ever since the introduction of IMR4350 in 1940, and certaonly after mil-surp H4831 in the 1950's, but the weird, antique pressure standards for commercial ammo kept it from happening, even in handloading manuals.

Though I will check my copy of the first Speer manual, published in 1954....


“Montana seems to me to be what a small boy would think Texas is like from hearing Texans.”
John Steinbeck