Originally Posted by
Larry Gibson
I've slugged numerous milsurp 7x57s over the years and have found them to range from .286 - .289. Those barrels are not really "oversize" as that's the way they were intended to be. Our 7mm barrels are "undersized" actually and, again, based on the British 7mm sze. I've also collected numerous milsurp 7x57 cartridges from various countries going back to some 1917 and 1918 stuff. The bullets mike from .2849 to .2886". I also pressure test most of it that was in good condition (pulled bullets and inspected the powder) and would go bang. Those that wouldn't fire I put in WW cases with WLR primers. The psi(M43) measured were right up with modern standards. Those that think those old M93/M95s were "designed" for only 45,000 psi are sadly mistaken.
FYI; the 1917/18 (Spanish made) 172 gr milsurp ammo ran 54,500 psi at 2295 fps out of my 22" barreled M95 (original milsurp barrel, just shortened). The 154 gr PS 50 & 51 ran 59,400 psi at 2442 fps. Most of the other 154 gr milsurps also run 55 - 60,000 psi. Cavim 84 is really good milsurp and ran 45,700 psi at 2590 fps with the 139 gr FMJBT, it is pretty accurate in my M95 also. Both Remington and Winchester factory 175s run 2380 fps at 48 - 50,000 psi. I push the Hornady 175 RN at 2400 fps with 4831 at 51,800 psi with excellent accuracy out of my M95 and it is quite deadly on big game.
Larry Gibson