Never shot the .458 Win Mag, but a .45-70 Marlin GG loaded to 2100 fps
with a 405 Rem JSP is pretty attention getting. That is a 7.5 lb rifle, and
the stock is not exactly optimized for recoil reduction. Did a five shot
group at 2000ish and a five shot group at 2100ish and decided that I
was entirely done with that end of the .45-70 load spectrum. I had added
a good Kick-EEZ pad, very effective, first thing when I got the GG. Same
bullet at 1750 is very shootable and kills very well on large stuff like
wildebeest and zebra.
Add 100 grains and 50 fps, not going to make it more fun, although most
of the rifles are more in the 11 lb range, with better stock shapes, has to help a
good bit.
I was on the bench, too, chronoing and shooting groups simultaneously.
My clearest memory is a mental note - "do NOT do this again." Not truly
painful, no injury, but really unpleasant stomping and banging. Hold on
tight, pull rifle into shoulder with left hand, sit up relatively straight, do not
lean fwd into it.
Bill