Just a few comments re: powders for the .458. I learned from my .45-70 days, including the Ruger No.1s, that almost anything that would work in a .223 Rem would do so in a .45-70 and a .458 Win. However, from considerable experience - and any limitations of powders being available in this area - I settled on three Hodgdon propellants that were usually available locally: H4198, H335 and H4895. I've never needed anything other than those three. I still have 'em, though H4198 is getting low. It (H4198) is far more useful in those two .458-calibers than realized by most .458 WM or .45-70 fans. And it is very temp resistant (IMR 4198 is NOT the same).
Comming up this Saturday (God willing); My blog is: Comparing two African greats, The .375 H&H and .458 Winchester Magnum. In the .458, I showcase one load; the 404gr SH for a moose hunt to 500 yds! It's based on my test results in the Ruger No.1H firing the former Barnes 400gr X-Bullet... thought some might be interested.
