nope you are way way out of my league, 30-06 is my biggest, which is about .22 size in compairson to what you are loading. I like my right shoulder too much.
.458 win mag is my pumpkin roller, it loads mostly like most other straightwall, not too many tricks.
Many powder loads are near compressed and a heavy crimp is often called for just to hold the bullet in place, with the Lott you shouldn't have near the compression issue although I would still do a decent crimp on it.
I'm not much help with bullets, I only cast for mine, never bought it any jacketed bullets! Mine is in the no.1 so accuracy has been a challenge but get yourself a good 500 gn bullet designed for 45-70 long range stuff to try out if you are going to cast for it. Buying bullets is just too expensive for me.
Don't know if it's just my setup but the primer pockets get dirty faster than any other caliber I have, they need a good scraping every reload.
I have produced best results (and least recoil) with IMR 4064 and 3031, FYI H4198 behind a 500 grn HURTS.
From what I read, that's why the 458 LOTT was born. John Lott shot something ( cape buff? ) with a 458winmag, and then nearly got killed... so redesigned it as 458 lott.I've been thinking about a 458 win, but a buddy shot a nice blk bear 400 lber with his 458 and the bear ran right at him, second shot stopped the bear just 15 yards from my buddy. .
i'll askt he dumb question..I used to load for .458 Win Mag. (Have steel plates in my neck so that ended).
Problem with the .458 is either you want to load a range load that won't beat you up too bad, or you want full power loads that just a few at the range and you're ready to put it away.
I loaded 500 grain Sierra sp bullets with IMR-4895 powder. Those were brutal 95% loads. I also loaded my own cast Lyman 385 grain bullets with puffed wheat as a filler, and I could manage 1 1/2 to 2 inch groups at 100 yards with express sights. Those loads were about equal to a .30-06 with 180 grain bullets and a stiff load. The 500 grainers were extreme in recoil, muzzel blast and muzzel flash with the short 18" barrel.
My wife thinks I'm still cute, but you got the grey whiskers part right. I've used GREX buffer and more recently cornmeal. My accuracy load in the Sharps uses IMR 4198 and a cast 518 gr. round nose, ww, with an over-powder card and cornmeal. I get right at 1/2" at 100 yards for 5 shots with that setup.410 has the answer. The charges I used with those 385 grain cast bullets only filled about half of the case. I had much better ignition/accuracy when I started using puffed wheat as a filler. Have been reloading for many years, and I would not recommend doing that if you aren't ugly and have grey whiskers like me, or unless you do a bunch of homework before doing it.
I got his name wrong i guess .. it's jack. here's a wiki article.. I could have sworn I have read it in a magazine too though.I think the Lott was born because of the compression issue with the powder in the .458, not because it needed more power. I've not had much compression problems with 4064 and others.
Don't go to any extra trouble.. but if you are ever making some gascheck slugs, could you send me a couple to load and try. I'd be glad to pay the shipping, etc.I'll have to pull up mold numbers but next time I cast some I can send you some to try out!