Thank you. So if the Speer manual is correct, the 375 Ruger/ 416 Ruger brass should have a slight more capacity in equal calibers.
Yes, both by calculation and actual measurement, the 375 Ruger case has significantly more capacity than the 458 WM case. I routinely load 83-85 grains of extruded powders in the 375 Ruger or in my wildcat 404-375 Ruger with monolithic solids - which are long for weight - or Barnes TSXs . No significant powder compression is needed to load these bullets and stay withing the COAL required in the MKII/Hawkeye magazines of 3.390-3.40".
Getting that much powder into the 458 WM case and then seating a 450 grain monolithic solid requires significant compression, unless you stick to spherical powders, like AA-2230. I was able to load 80 grains of 2230 behind a CEB BBW#13 today at COAL = 3.390" without trouble but the same charge with Varget required significant compression with the same bullet.
Is life so dear, or peace so sweet, as to be purchased at the price of chains and slavery? Forbid it Almighty God! I know not what course others may take, but as for me, give me liberty of give me death! P. Henry
