458 WM Cast Loads

[Johnch]

Well a 2+ year project is about done
I bought a used rifle with a junk barrel for the action
Had a good friend install and chamber a new barrel for me
I replaced the old stock with a laminated one , glassed the action in after I installed a recoil bolt ( not that I plan on shooting full power loads )
I am just finishing putting a Leupold scope on it

So now I am looking at the empty cases and a bunch of 400 gr cast bullets from a NOE mold I have

And .....I have no clue as to what I should use as powder or how much

I want to start out easy on me and load a 1700 fps or so load to get used to the rifle
To start I plan on punching holes in paper and clay targets

I may use about the same loads for deer this fall .....I figure it should kill deer just fine :bigsmyl2:

Thanks and have a nice day

John

[lobowolf761]

You can try Imr 4227, Unique or 2400. If you can check the loading data in the Lyman Cast Bullet Handbook.

[Tatume]

http://www.hodgdonreloading.com/

Hodgdon only shows Trail Boss for cast bullets, but you can use reduced loads for 4895 and 4198 safely. Look at the starting loads for jacketed 400 grain bullets, then reduce judiciously.

[MarkP]

Last weekend I shot some 405 gr FN PB over 14.0 gr of Red Dot in my 458 WM, shots were all touching at 75 yds. I would guesss these were in the 1,350 to 1,400 ish range, judging by the time to hear gong strikes at 165 yds. Like shooting a 20 ga single shot in terms of recoil.

[Johnch]

Thanks
I only have 10+ lb of 2400 .... but I am sure I can find a load that works

John

[MarkP]

John, Here is a scan of an older Alliant complementary reloading guide (1995) that lists some loads for the 458 WM using 2400 powder.147624

Not uploading PDF file here is the DATA:
35.0 gr 300 gr Hornady, 1,590 fps, 13,500 CUP
30.0 gr with 385 gr cast , 1,290 fps, 14,200 CUP.
35.0 gr 500 gr Hornady FMJ, 1,415 fps, 32,600 CUP

If I can find the time I am hoping to try some 2400 loads this weekend, I will try to remember to bring a 9 V battery for the chronograph and get some velocities of the 2400 loads and Reddot loads. I will post results.

Take Care --- Mark P

[W.R.Buchanan]

Have a look at .45-70 loads. The .458 Win Mag is essentially a bigger .45-70, so to push the same boolits at .45-70 velocities will probably take the same amount of powders it does in the .45-70 case.

Lots of info on Cast for .45-70's in every loading manual.

Hope this helps.

Randy

[Tatume]

Actually, the 458 Win Mag is quite a bit bigger than the 45-70, and takes substantially more powder to achieve the same speeds. For example, from the Hodgdon online manual, 50 grains of IMR 4198 in the 45-70 and 60 grains in the 458 Win Mag will result in about 2100 fps with the Speer 400 grain jacketed bullet. The point I am trying to make is be careful not to load that big case with too little powder. The faster burning powders are safer to experiment with, but the slow burners can get you into trouble.

[Baryngyl]

Have a look at .45-70 loads. The .458 Win Mag is essentially a bigger .45-70, so to push the same boolits at .45-70 velocities will probably take the same amount of powders it does in the .45-70 case.

Lots of info on Cast for .45-70's in every loading manual.

Hope this helps.

Randy

That is basically what I did, I chose the faster powders and started close to the MAX charge for the 45-70 as my starting charge, I had not worked up the best load possible before the gun was stolen but I did have 2 loads that were pretty good.
A 405 grain LEE bullet and their 500 grain, not sure of actual speeds as I did not have a chrono yet, but the 405 was pretty zippy it seemed and the recoil was about the same as 12ga 1.1/8 oz target loads but the 500 kicked a bit more then the 12ga 3.1/2 heavy loads did.


Michael Grace

[oldred]

I shoot 500 gr cast in my 45-90 which is very nearly a 458 magnum case but without the belt, nearly the same case capacity and dimensions. I have used 3 different powders with very good results, Varget, H4895 and AA4064, 50 gr of the 4064 pushes that 500 grain cast to 1700+ FPS and according to AA's specs does so at about 28,000 CUP. I like the 4064 the best but Varget and the H4895 are about a toss up for a close second choice.

[MarkP]

147647 Some IMR data to compare with the Alliant Data ............. I like the older handouts as they listed most all powders with pressures and velocities. Not claiming they are all ideal loads but they were tested and I find useful for a benchmark.

45 gr of 4227 yields 1,665 fps and 52,700 CUP with a 510 gr SP

[tazman]

Back about 35-39 years ago I had a 458 WM which I proceeded to load with cast boolits. I was using a Lyman 462560 as well as a couple of smaller Lee molds. I used IMR3031 with all of them from light loads up through full power shoulder bruisers.
The 462560 shot really well in that rifle. You wouldn't believe the penetration you get with a 545 grain slug made from water dropped linotype with a full power load. I never found anything that would stop it so I could recover the boolit. I shot a couple of them into a brown clay bank and tried to dig them out. After digging in 4 feet and still not finding anything but an empty hole I gave up. Water jugs stood no chance at all.