Home Forums Hunting & Shooting Express Rifles and Big Bores Only The great 458 Winchester. Everyone should own one at least once

Michael McCourry aka Sir Michael, aka Michael458, aka Doc M of MIB (McCourry Institute of Ballistics)
is the "M" of "B&M" rifle and ammo fame.

He has given permission to share his .458 WinMag handloading data here.
Pressures and velocities are measured at the MIB laboratory.

Anyone handloading ammunition does so at their own risk.
Rifles and components do vary, as do the reloading results involving them.
Start about 10% below maximum load and work up, for any MIB data.
I have been known to use Sir Michael's data to good effect.
Children should not try that without adult supervision.

Slideshow below is my summary from reading the MIB data and copying photos:

Here are my results when copying the MIB load data with the 450-gr CEB FN brass solid
and AA-2230 as propellant.
I used only 5 bullets for complete workup.
No other handload with that bullet need apply for my .458 WinMag.

We are awaiting more pressure data on a 20"-barreled .458 WinMag from MIB Laboratory.
Some people like them short.

Good to know you only lose about 72 fps in chopping from 24" to 20".
That means 2500 fps in a 24" becomes 2428 fps in a 20" with a low pressure 404-gr Shock Hammer at COL of 3.380" (Norma brass if WW/Hornady/RP too hot ?).
That means 2349 fps in a 24" becomes 2277 fps in a 20" with a sub-59,000 psi 450-gr CEB brass FN at COL of 3.360" (WW/Hornady/RP brass: All good).

I SWAG that is about the velocity and pressure Doc M of MIB will find if he tests the CEB with two bands out of case, with post-2016 vintage AA-2230,
F215 primer, and WW-Super, Hornady, or RP brass.
WLRM primers will do fine, they are very close to F215 and the same-same GM215M.

Still waiting for Pac-Nor to send a 10"-twist barrel for 24" length for an FN Mauser 98 .458 WinMag.
That will be tried for comparison (by me) against a Pac-Nor 1:10" barrel of 19.75" length on the .458 B&MW Winchester M70.
Those two cartridges have same throat and have same case capacity when COL is adjusted properly with the specified bullet.

That fast twist will allow the long and pointy VLD bullets to be tested at supersonic speed,
and all sorts of shorter bullets to be tested at subsonic speed.
And the 24" Mauser will be threaded for suppressor.
The Vietnam fiasco of the suppressed .458 WM-1.6"&1.3" with 500-gr FMJ at 1100 fps can be improved upon, no doubt.

SLGPT,
Join the Square Table and pick a SIR NAME, please.

There are no good 400-gr FN solids for the .458 WinMag at present,
unless the Woodleigh HYDRO 400-grainer becomes available again,
or some other maker (Hammer or CEB) decides to make one that has a band structure suitable for use
in both .458 WinMag and .45-70 Govt.
The Woodleigh HYDRO does that.

The 450-gr and 500-gr FN solids are best choices.
You can make them work with the 404-gr Shock Hammer.
the 450-gr TSX and 500-gr TBSS work a charm for the .458 WM+ at less than 3.6" COL.
He-men like Sir Jerry like that combo.
He also has a good load combo with the 404-gr SH and 500-gr TBSS.
It is all good.

I like the idea of 3.38" COL or less in the +3.4" mag box found on most factory .458 WinMag rifles.
Sir Jerry has demonstrated that too, in Browning Safari FN Mauser.
See his copy to you.
Hard to beat.

Oh yes, my broken foot is healing well. Just the second metatarsal was fractured mid-shaft, X-ray yesterday.
I'll be hiking in good boots, might shoot some more deer with 404-grainer,
before I get back to Alaska or Africa.

With the understanding that I am not an experienced 458 shooter and have nothing to add to this great caliber yet, how about Sir Roo?

I found some AA 2015 locally, but there is not much choice in powders around here. I like to keep as few powders on hand as possible so I look for versatile powders. Varget seems to be pretty universal. I used it in 308 many years ago, and now with 458 and 375 coming up for reloading, it seems to be a good choice. Anyone use it for these calibers? Better or worse than anything else? Any favorite loads? Is there a more universal powder I should look at?

Also, the only problem with this thread is trying to go back and find specific data!

Yessirree, Sir Roo it is.
You get a Bill Bagwell Bowie tap on the shoulder at the Square Table Rendezvous,
whenever that happens.
Arise and sally forth with Varget.
Many decent loads with that I am sure.
It is my favorite powder in the .404 Jeffery with any bullet weight.
Top performer in the .500 Jeffery too, from experience with one load there.

Alas, I have not tried it in the .458 WinMag,
but if I did, I would first take the Woodleigh manual max loads for the .458 Lott using VARGET:
500-gr Woodleigh RNSN, 83.0 gr VARGET >>> 2220 fps, not compressed
500-gr Woodleigh FMJ, 83.0 gr VARGET >>> 2210 fps, mildly compressed
550-gr Woodleigh RNSN, 79.0 gr VARGET >>> 2110 fps, not compressed
550-gr Woodleigh FMJ, 77.0 gr VARGET >>> 2050 fps, mildly compressed
Those .458 Lott loads would be close to 3.600" COL or less, and 62,500 psi or less.
If you load a .458 WinMag to 3.600" COL with those bullets and powder charges,
you will most likely have better performance regarding velocity and pressure.
But start a little lower than max .458 Lott load with the .458 WM+,
and you will be able to work up to max .458 Lott load at least !

Standard SAAMI .458 WinMag loads with VARGET follow (Woodleigh manual),
not the fastest loads but not far off,
and VARGET is supremely accurate and uniform, temperature insensitive, and works great with mild compression.
The Woodleigh VARGET data for 24" barreled .458 WinMag at 3.340" COL or less and 60,000 psi or less, most likely:

400-gr Woodleigh PPSN:
74.0 gr VARGET >>> 2210 fps, not compressed
77.0 gr VARGET >>> 2310 fps, mildly compressed

480-gr Woodleigh RNSN:
72.0 gr VARGET >>> 2050 fps, not compressed
77.0 gr VARGET >>> 2150 fps, mildly compressed

500-gr Woodleigh RNSN:
70.0 gr VARGET >>> 2010 fps, not compressed
74.0 gr VARGET >>> 2110 fps, mildly compressed


550-gr Woodleigh RNSN:
69.0 gr VARGET >>> 1960 fps, not compressed
72.0 gr VARGET >>> 2015 fps, mildly compressed

I always go for VARGET as a replacement for RL-15, grain for grain, VARGET is the better powder.
Hodgdon EXTREME.

Well, I just picked up my third .458 WM on Monday of this week.
This is a running total for the past 30 years.
This one is a semi-custom Ruger M77 Mark II.
Came with dies and some brass.
I am planning on deer hunting some with it.
Anyone have any good Whitetail loads worked up?

I’m planning to use 250 Monoflexes and H4198 in mine. They shoot well and should air out a deer easy enough I think. They are just about 2950 if I remember correctly.

Lots of good and useful info Sir Ron, many Thanks for the lessons.

rodeojoe, welcome to the Fire, beretzs' load above will be great for low recoil flat shooting white tail deer.

Quick story about your AO, one cold winter night in 2013-2014 i was headed to a 24hourcampfire pig shoot in Monterrey Tenseness, a bit West of Cookeville i blew a #4 injector line on my dodge cummins, i called boss man, he asked what yardstick on I-40E i was at, i told him, in just a little bit two tan unmarked vehicles pulled in behind me with a rolloff wrecker behind them, i take it they were some kind of cops, do you guys have a TBI, state investigative service or some such?

Anyway, they got my truck loaded on the wrecker, i rode in the wrecker to the Dodge dealership right there in downtown Cookeville, the two tan cars went on and parked across the street as we turned into the dealership, we pulled around to the service bays, up walked a man in a grey work uniform smiling with a wad of keys in his hand, he unlocked and rolled up a big door, the wrecker driver dumped my pickup off on the ground, we pushed it backwards into the bay, the service guy went and got a new injector line, installed it for me right there, jumped in and we rode around the building to a detail bay, he fired up a pressure steam washer and washed some of the diesel fuel from under the hood and down the drivers side of my pickup.

I drove him back around front, he closed and locked the door, this all happened at 9 p.m. at night, the guy didn't charge me a dime, wouldn't even take a 100 dollar tip offer, the wrecker driver said no charges either, they shook my hand and sent me on my way, that was a chit load of great hospitality and service i experienced in your town and state that evening, you see, i was prepared to sleep all night in a cold pickup, i had a load of pretty expensive guns on board for the pig shoot, when i got back home, i told Wife if we ever leave this farm in Oklahoma, we're moving to Cookeville Tennessee!

As i pulled up on the get on ramp i noticed the two tan cars again, they followed me a for a few miles then exited up the interstate a bit, nice guys all around.

Thank you Sir Ron, for the hospitality as well as the load data. I have some 404 Hammers on the way and load data for them with the AA2015. I will incorporate the Varget data and see which works better. Just need to get some cast bullets now for cheaper practice. I suspect most of my shooting will be with 400g at around 2300, but I will just have to see.

I do have an Ontario Helles Belle to bring to the gathering, but no real Bagwell knives here, I am afraid.

Glad you enjoyed your trip to this part of the country.
And I-40 thru Monterey is watched very closely for all kinds of trafficking, drugs being at the top of the list.
They seemed to have overlooked my invite to the pig shoot that year.
Great story, helps take away some of the shame of Al Gore coming from this part of the country!

Riflecrank, I have a New Haven CRF .458 M70, and I'd like the ability to load the 3.6" rounds. Thanks for your post on how to do it... I found the ejector online, but I can't find the #1110 box. I did find a #1450/1460 box at Midwest Gun Works, but don't know if it will drop into my Super Express. Any suggestions?

Also, at the risk of further digressing from the current bullet topic, as a thought experiment, is there any advantage to reaming a .458 Win throat for a cartridge such as a .458 WSM/B&M that is built on a short action with a 2.8" magazine limit?

rodeojoe,

Sir Joe is taken. How about Sir Rodeo ?
I have a Ruger Mk II .458 WM with Shilen No. 5-1/2 Sporter contour barrel
that can be switched from HS Precision to Zytel Canoe Paddle stock, depending on my mood.
I love it, great rifle.
What bullet weight do you want to hunt deer with ?
My last two deer were taken with the Ruger Mark II and 400-grainers.
We have loads aplenty here, but you gotta narrow it down to your druthers,
so many possibilities with the incredible, versatile .458 WinMag,
from 250-grainers on up.

Sir Jerry,
That is quite a tale of VIP treatment.
You must be quite the VIP.
I have fond memories of Alan Wilson's Wilderness Lodge,
four trips there over 20 years ago ...

Sir Bevan,
Dang, the #1110 is discontinued.
The #1450/#1460 (chrome-moly/stainless) look like the ones used in the FN/SC M70, not the Connecticut Classic.
Best to just pop the spacer out of the rear of your current box.
At MGW, #1030 looks like the Classic box and is specified for .458 WinMag, with block at back of box: NOT DISCONTINUED at MGW !
Get one of those to practice on, to preserve your original box.
The rear block can be popped out with a sharp chisel,
or you can drill out the four little spot welds to make it easy.
Use a flashlight and look down into the block to see where the welds are.
If you do not like having four little holes at the back of the box, they can be filled with solder and stoned smooth.
The back of the box can be easily straightened up after any minor mutilation.
With the block removed, there will be a split than can be JB-Welded or soldered and stoned smooth.
Or just leave as is and just smooth and square the split so all is flush when held in the action by the fit into bottom of action.

My .458 B&M on a WSM M70 Classic has a 3.0" box and is limited to 2.95" COL.
I thought it needed to be re-throated with a .458 WM reamer.
It is now a .458 B&MW.
It will single-load 3.34" COL now and has same case capacity as a .458 WM 3.6" when I do that,
with same bullet of adequate length to reach.

Thank you very much, Sir Ron!

LOL rodeojoe, yes, fun times on those pig shoots, i wish you could have made some, we would have had a blast, still not sure what kind of coppers those were, i didnt ask either, just happy they showed up.

Sir Ron, LOL, no vip here Sir, i dont know who Doc called or exactly what he said, but it may have been along the lines of "we need to do whatever it takes to get this crazy hillybilly redneck fixed up and sent on his way, and send me the bill" ; ] you see, i was carrying three double rifles, an 8 bore rifle, a couple three Sharps rifles and several handguns, i would have hated like hell to make a damn big mess along the roadways of Tennessee in the event of an attempted carjacking/robbery type deal.

The Wilderness Lodge was a fun place, i miss those gatherings with the 'Fire crew.