Agree on the grabby/sticky "lubricity" (or lack of it) with the soft copper-jackets compounding the barrel friction with their full-bearing shanks. Swift A-Frames do that too. The Hammer PDR bands and GSC HV drive bands do seem to give higher velocity at lower pressures by my SWAG-ometer readings. Ditto the slick, bronze/brass banded Federal TBSS with lead core, and the banded brass bullets from CEB and the defunct Barnes Banded Solids. Extra bullet length allows getting pressures and velocities up by increased seating depth with lesser powder charge. One can make a 3.34" COL almost equal a 3.60" COL, but not quite. More powder and more recoil with the faster 3.6" COL. Hell's bells, a maximum load in a .458 WM+ is going to out-do a maximum load in a SAAMI .458 Lott in many ways.
On a different subject: Alas, my .375 H&H M70 Classic Stainless from New Haven was rechambered to .375 WBY long ago. A .458 re-bore by JES and rechamber won't clean up the chamber. Less case-body taper in the .375 WBY than in the .458 WinMag is the culprit. At 2.520" from breech face, the .458 WinMag chamber ends at 0.483" reamer max diameter, where the case mouth chamfer starts. At 2.407" from breech face , the .375 WBY reamer diameter is 0.496" max diameter, where the WBY shoulder starts "venturifying." That would make for a bulged and ringed .458 WinMag chamber if not set back. Looks like a new 1:14"-twist barrel is needed, for a switch-barrel .458 WM+/.375 WBY on the M70.
First comes the fast-twist M98 .458 WinMag with 24"-long, Pac-Nor No. 5 sporter contour, 1:10" twist. Heaviest bullets subsonic and suppressed for head shots on any varmint at 100 yards. No shortening of case to 1.3" with 2-foot-long, fat suppressor shroud around the barrel of a 14-pound rifle is needed. Just sayin'. AA-2230 was developed for the 223, haha.
Ron aka "Rip" for Riflecrank Internationale Permanente NRA Life Benefactor and Beneficiary .458 Winchester Magnum, Magnanimous in Victory THE WALKING DEAD does so remind me of Democrap voters. Donkeypox.
