The “458 Winchester Magnum, all the cartridge you’ll ever need” thread

[ldmay375]

The CEB Safari Solid #13, 325 grain .458 is poster child for design and construction.
I think there is a chap on this forum that give the field results of this bullet, on an elephant out of his buddy's 450 Nitro. Amazing bullet. Who the heck would have thought a 325 grain .458 bullet could perform as such ?? Though the tests certainly indicated the probable outcome.

 

[Slyfox72114]

Hello Slyfox,
Is the rifle not marked as a "450 Ackley Magnum" ?
That is the one we think of usually.
It came along after James Watts started it all with his ".450 Watts Magnum," shooting first in 1949.
Watts visited Ackley and Buhmiller, looking for a barrel early on in his dreaming stage.
It does seem Watts beat both of them to the .450-bore on the 2.85"-length H&H Magnum case.

The .450 Watts Magnum has a straight, belted case, no shoulder, and is 0.050" longer than the .458 Lott wildcat latecomer (1971).

The .450 Ackley Magnum had a 2.85" belted H&H case length also, but had a tiny shoulder located at 2.407" from the base face of the brass case.
Shoulder hemi-angle angle was 20* (cone angle 40*).
Shoulder was 0.503" diameter at 2.407" length.
Neck-1 was 0.487" diameter at 2.429" length.
Neck-2 (case mouth) was 0.486" diameter at 2.850" maximum brass length.

If you have a .450 Ackley Magnum, it really would be best to get the proper handloading dies and some basic cylindrical H&H Magnum brass to size down and shoot, and some properly headstamped brass for Africa. And the rifle needs to be engraved/stamped properly as to chambering/cartridge on the barrel.
The .450 Ackley Magnum is well known and bragged about often by magnificent author Terry Wieland. Proper brass and dies should not be too hard to find. Google away.

I have a .450 Barnes Supreme by Fred N. Barnes, from the 1950s, which is very similar to the .450 Ackley Magnum. Barnes used both Brevex and 1917 Enfield actions for the Barnes Supreme line of proprietary cartridges he offerred.
Long brass, tiny shoulder, load data would be interchangeable.
I also have a .416 Barnes Supreme, another one from the 1950s.
Both of my Barnes Supremes were built on Whitworth MK X actions in 1987, just before Remington came out with the .416 RemMag, boo-hoo.

Watts also did a 2.5" .450 Watts Short before the .458 Winchester Magnum was released to the public in 1956, after James Watts "released " it to Winchester in the year 1954 or before.

Fred N. Barnes was offering his proprietary 450 B-J Express (Barnes-Johnson) in a lineup of "short magnum" cartridges from 7mm to .458 caliber, in the early 1950s.
He claimed his 450 B-J Express was being chambered and rifles sold "several years before Winchester added the .458 to their line."
The B-J express line all had 2.5" belted H&H Magnum ("short magnum") cases with the case body length to shoulder being 2.125", shoulder diameter 0.500", shoulder hemi-angle 35*.
He said in his March 15, 1958 pamphlet:
"450 B-J Express
The most powerful of the B-J Line. Shoots a 500 gr. bullet at 2200 f.s. Works perfectly in any standard length action. Rifles chambered for this cartridge will also shoot the new .458 Winchester factory cartridge.
While this is a so-called improved version of the .458 Winchester we chambered rifles for the .450 B-J several years before Winchester added the .458 to their line."

Seems Fred N. Barnes might have given Winchester ideas about the .338 WinMag and .264 WinMag too.

So when you say "improved .458" it stirs up thoughts of something other than the .450 Ackley Magnum.
Most likely it is a .450 Ackley Magnum if built on a 1917 Enfield and has a +3.6" magazine box internal length.
Mind your P's and Q's and get a chamber cast if any questions.
Firing a factory .458 Lott cartridge in your rifle to get a short-necked version of the .450 Ackley Magnum would be a sort of chamber cast, in brass.
An actual chamber cast would tell you more about the throat.
Lacking that, check the throat length with dummy cartridges using .458 Lott brass before shooting it.

Riflecrank
Sorry I missed your response.
I just bought this rifle at a local auction. The auctioneer called the gun collector and he said his father or grandfather bought this from PO Ackley and it’s a 458 Ackley improved this past weekend. I took the stock off thinking I’d see some markings and there’s zero markings on the barrel that indicate what it is , so that has me rightfully concerned to try to put a bullet off in it based on what this gentleman said your advice is much appreciated. Thank you.