458 Win Mag reduced loads (wanted)

Hi all. I am looking for reduced loads for a 458 Win Mag. I do have Lazer Cast 350 grain and Hornady 350gr round nose bullets.

Welcome to the Guide, Slider.

I would be looking at .45-70 loads that do not use a ball powder. How much luck you will have with those undersized commercial cast bullets I do not know - I would be prepared for significant lead fouling if you try to push them very hard. A Lewis Tool from Brownells will help if you go too hot and fill your grooves up. I would want a cast bullet to be .460-.461" for best results.

hard to add to the above except that those cast boolits will give you problems if they don't fit.
and will definately lead up the bbl, mainly because of how hard they are.
if however they do fit i'd look for loads in the 45-70 range and in the 1300-1400 fps range to work from

The ones I have are .459 would they be OK at 1800fps?

Maybe. It can't hurt to try, other than some vigorous exercise if you have to clean out lead fouling. It depends on the actual size of your bore. They can vary by a thousandth or two either way - that's why slugging is always recommended before shooting cast in a rifle to save time and hassle vs. the trial & error method. You also want to thoroughly clean any possible copper fouling out of the barrel as with some barrels it can make a really big difference.

Would I be better off to just shoot the jacketed 350 Hornadys?

If you want convenience, shoot the jacketed first, there are fewer variables involved in working up an accurate load. I don't know how low you can load them accurately. It depends on what your rifle thinks of the bullet you have and then try several others lighter in weight to see if it shoots better or worse with any of them, and try several powders.

If you want reduced loads for your .458Mag (and I know I sure would), cast is the way to go, but with a bullet of the correct length, diameter, lube, and alloy for your barrel. You can try anything from round balls to 500+gr bullets - and should - to find out what your rifle likes best. Maybe you will get lucky and hit a good accurate bullet in one or two tries, maybe more. It can take more patience than with jacketed because there are more variables involved, but is well worth the time and effort for what you learn in the process. Never try reducing ball powder loads below START levels. Bad things can happen. IMR extrudeds and Alliant extruded and flaked START loads can be safely reduced at least by10-15% for 300gr+, and even lower with lighter bullets. Cast bullets always operate at lower pressures than jacketed of the same weight with an equal charge of the same powder, etc.

You could learn to cast your own 8) :twisted: [smilie=1: :mrgreen:
or you could start out by ordering a selection of different weights and profiles, custom size and alloy, from here: http://bullshop.gunloads.com/
and you'd know what moulds to look for if you want to get into casting them at some point.

I'm sure if you searched over on CastBoolits, you would likely find some cast load data, weight and design recommendations to start work with.

OK Thanks for the help.

I just reloaded some 45-70 loads with a 70% Trail Boss load. 925 ft per second three shot group 405 bullets that you could cover with a quarter at 50 yards. Look up Trail Boss powder and you might be happy with plinking loads.

Methinks I'd save th Hornadys for more serious shooting but if not, I suppose the starting load for the .458 might not kick too bad. It's been well over 40 years since I owned a .458 so the memorey banks are not all that good that far back. I lost all my loading notes in the move from Nevada to California so I don't hve anything to work with. Dunno if this will help, but I shot bullets sized to .459" in two different 45-70 rifles. One was an early New Model 1895 that had Micro-groove rifling. I gou fairly concistant 2" groups at 100 yards with a Receiver sight and groups like that from my bad 73 year old eyeballs is something I consider pretty darn good. The same load from my Ruger #1S went into 1.5" using a 2.5X scope. Velocity was, IIRC about 1750 FPS. Powder was SR4759. Bullet was a 330 gr. cast hollowpoint.
Paul B.

Try .45-70 loads . There are 3 pressure levels ,

God bless
Wyr