Okay, but I really am gonna start my own thread!   



                                              Joe. 

A friend of mine and I went to the range with the .458WM, 45-70-500 and the 375 ouch and ouch (300gr).  Max loads.
I shot about 50 he shot about 30.
Both of us were shooting from the left shoulder towards the end, as the right was too tender.
Fortunately I don't bruse - slight yellowing of skin.  He was black from elbow to chest.

So one would do much better with muzzle breaks, but I wonder about merely a recoil delaying device.

When I first started shooting ASSRA at Etna Green a few years back the ONLY rifle I had was a 45-70 Browning sporter---not one of the long heavy Creedmoor/BCPR versions--  it was the 1878 one with no tang and a light short tapered barrel.

I was breech seating the original Lyman Matthews 500 gr tapered bullet with some fairly stout loads of smokeless.  alloy was critical as was a good solid breech seating tool.  I also used cork wads seated the wad's thickness off the powder--mostly to keep from spilling it as I chambered the case.

Yeah it beat me around some, but once I got behind the bench rather than alongside the gun---and did the Dale-job on the trigger.  the thin sporter stock was a PITA off the bags.  but in spite of it all I managed a few low 240-s in the Schoyen----which I've had a hard time beating since with nominally more appropriate equipment.   Maybe I ought to did it out of storeage.

One thing for sure---it was a LOT less wind sensitive --in fact when I was shooting it I had no flags, probes or any other such doo-dads.

I see no reason it shouldn't work for you---given it is a bigger horse, kicks harder and is more expensive to feed.   It's just a matter of finding the right balance of the bits'n pieces.

Good luck