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

The question was regarding the .458 B&M, not .458 WM. I'm certain Sir Ron knows.

Bob
www.bigbores.ca

Sirs,

Nice link on a case capacity reference from Sir Khulu,
but the author notes they are approximate, and "The values are averages from several sources."
Still it is excellent reading and instruction on technique for measuring case capacities oneself,
and it's the way I do it.

Here is a very specific case of case capacity comparison for the .458 B&M to the .458 WM.
My technique was same for both, done at same sitting.
One lot of brass for each, and the final result was corrected from the average length, shorter, case length actually used
(once-fired brass with spent primer sealing bottom of case)
to a specified maximum case length desired for comparison.
This uses a .458"-diameter right cylinder of water 1.000" tall with weight of 41.66 grains water to fill that volume.
Therefore, each extra length of case neck of 0.010" adds 0.4166 grains to case capacity.
True that, in this case of cases.

As originally conceived, the .458 B&M was to have a maximum case length of 2.295" and COL max of 2.995", IIRC.
In practice it had to be shortened to 2.240" max brass length and it still works within the constraints of 3.000" magazine box length.
It also had a very short throat.
Almost no throat.

Average for 10 cases of .458 B&M from Quality Cartridge:
2.295" brass = 97.3 grains water
2.240" brass = 95.0 grains water
The .458 B&M brass formed from shortened .300 RUM cases from R-P have same case capacity.
Same flavor of brass.

Average for 10 cases of .458 WM brass from R-P:
2.500" brass = 95.3 grains of water
2.490" brass = 94.9 grains of water

So for all practical purposes, case capacities are identical for
.458 B&M at 2.240" brass length
and
.458 WM at 2.500" brass length

Just call it 95 grains water, like the default value in QuickLOAD for 2.500" .458 WM brass.

Norma .458 WM brass actually measured was 99.3 grains water.
Norma .300 RUM brass turned into .458 B&M might also be bigger.

Peterson Wildcat Tube brass once-fired and corrected to 2.500" length held 93.8 grains water.

That is a good relative comparison, as good as any, not absolute, just relative.
That is no theory of relativity, it is Viking Law.
So, when loading the same bullets in those two cases of those trims,
both will have the same net case capacity when the .458 WM COL is 0.260" longer.
A .458 B&M with COL of 2.995" and a .458 WM with 3.255" have same net case capacity.
A .458 WM with 3.340" COL will have a greater net case capacity by 3.541 grains of water.

To equal the case capacity of a 3.340" COL .458 WM with same bullet, the .458 B&M+ (long throat) must be loaded to COL of 3.080"
The .458 B&M+ loaded to 3.340" COL has same case capacity as the .458 WM at 3.600" COL with same bullet, same seating depth.
Both will beat a SAAMI .458 Lott at COL 3.600" with same bullet.
Higher velocity or lower pressure or both.

Thank you.
So if the Speer manual is correct, the 375 Ruger/ 416 Ruger brass should have a slight more capacity in equal calibers.

Yes, both by calculation and actual measurement, the 375 Ruger case has significantly more capacity than the 458 WM case. I routinely load 83-85 grains of extruded powders in the 375 Ruger or in my wildcat 404-375 Ruger with monolithic solids - which are long for weight - or Barnes TSXs . No significant powder compression is needed to load these bullets and stay withing the COAL required in the MKII/Hawkeye magazines of 3.390-3.40".

Getting that much powder into the 458 WM case and then seating a 450 grain monolithic solid requires significant compression, unless you stick to spherical powders, like AA-2230. I was able to load 80 grains of 2230 behind a CEB BBW#13 today at COAL = 3.390" without trouble but the same charge with Varget required significant compression with the same bullet.

True, all that.
The RCBS Cartridge Creator algorithm shows
.416 Ruger = 101.5 gr water
.458/.416 Ruger = 104.2 gr water
That is for a simple necking up of the .416 Ruger
and keeping max brass length at 2.580" for both.

My fire-formed .458/.416 Ruger brass comes out
2.565" in length.
Measured case capacity for that average is 104.47 grains water.
Correcting to 2.580" max brass length gives 105.1 gr water.

Mine is a .458 Win Ruger and can be loaded to same long COL as the .458 WM+,
which is a longer COL than the SAAMI .458 Lott can handle.

Sir Ron,
Thanks, my curiosity was regarding the B&M compared to the Ruger brass. I thought they were close. Though not certain of the B&M capacity.

I just had a .50 B&M made up. Capacity is the same as the .458 win.

Thanks. That should be a handy rifle. And knock snot from large critters.

Sounds like an interesting rifle. What are you planning to hunt with it? How is the bullet selection?

Since this has turned into a wildcatting thread, just a reminder that the .458 Win can have a 3.8" COL without messing with brass or barrels in some "standard" formats like the CZ 550 I once owned and now in my Ruger No.1H.
Bob
www.bigbores.ca

Bullet length and depth of seating determines useable case capacity. In my Ruger No.1H, all bullets are seated 1/4" into the case, and that includes the long 500gr monolithics.

Bob
www.bigbores.ca

Agree on the seating depth / Usable case capacity. The 3.4'ish magazines with the longer bullets, I use 3.37 to 3.38" COAL. Some of the shorter and dependent on nose projection, I am at 3.225". Some of the lighter / shorter ones the rear shank diameter and length limits me from seating longer.

In the 458 Winchester, the 325 grain CEB Safari Solid is my shallowest seated bullet. I have not done the math subtraction. I am guessing there about a 1/4" of bullet in the brass. This is seated about 1/2 way on the 2nd band, allowing 2 full bands inside the brass. This bullet seems very secure without crimping. Though I do a light crimp the a Lee factory crimp die.

Yep, some of my WFN/blunt-nosed, +500-gr, hardcast bullets will barely fit inside of 3.340" COL in the .458 WinMag.
And since they are sized to .460" or .461" to fit in a .458" or .459" barrel groove,
for best accuracy and least leading,
they will not even fit into a SAAMI .458 Lott throat at all !!!
I would have to load them to a little over 2.8" COL in the .458 Lott.
Deep seating, heh-heh-heh.
The SAAMI .458 WinMag opens a can of whoop-ass on the SAAMI .458 Lott again.

BTW, to Sir Bob, when comparing the .375 carts:
The only homologation of the .375 Weatherby that I am aware of is by CIP and the Pmax there is 4400 bar = 63,800 psi.
.375 H&H is 4300 bar = 62,350 psi, by CIP Pmax.
The SAAMI homologation for the .375 H&H: Pmax = 62,000 psi (and the older spec was 53,000 CUP)

That brings us back to the .458 WinMag versus .458 Lott homologations.
SAAMI .458 WinMag: 53,000 CUP and later refined to 60,000 psi
SAAMI .458 Lott: 62,500 psi, necessarily pumped up to allow it to compete with the .458 WinMag.

CIP Pmax for both .458 WinMag and .458 Lott is 4300 bar = 62,350 psi, and that makes good sense.
The CIP .458 Lott chamber eventually got revised to match the SAAMI .458 Lott's short and tight throat, nonsensical as that is.

African Dangerous Game Cartridges by Pierre van der Walt is a fun book.
It has listings of "Relative Capacity" in tables starting each chapter on a particular cartridge.
Good comparison tool for gross case capacity in grains of water.

.577/450 Martini-Henry (solid/drawn brass case version introduced 1875, UK): 120.0 gr

.45-70 Government (introduced 1872, USA): 73.6 gr

.450 Nitro Express 3-1/4" Rigby (introduced 1898, UK): 136.0 gr

.450 No. 2 Nitro Express 3-1/2" Jeffery (introduced 1903, UK): 169.0 gr

.458 Winchester Magnum (introduced 1956, USA): 95.0 gr

.458 Lott 2.800" (1971, USA)/.450 Watts Magnum 2.850" (1949/USA): 105.0 gr (some claim 107 gr and 109 gr respectively)

.458 Express 3" (introduced 2000, RSA): 111.0 gr

.458 African (introduced 2000, RSA, Pierre van der Walt's own wildcat of a 2.673"-long .404 Jeffery case): 115.5 gr

.460 G&A (introduced 1971, USA, 2.860" length case, full length .404 Jeffery case): 119.5 gr

.450 Rigby Rimless Magnum (introduced 1994, UK): 133.0 grains

.450 Dakota (introduced 1992, USA): 137.0 gr

.460 Weatherby Magnum (introduced 1958, USA): 141.1 gr

I will add these:

.458 B&M (introduced 2006, USA, Michael McCourry's wildcat): 95.0 grains with 2.240" case, 97.0 gr with 2.295" case

.458/.416 Ruger aka ".458 WinRuger" (my version introduced 2018, USA): 2.580" case holds 105.0 gr

.458/.338 Lapua Magnum aka ".458 Ted Williams Thumper" (my version introduced 2003, USA, 2.700" case length): 125 gr

Theodore Samuel Williams, August 30, 1918 -- July 5, 2002.

I sure hope his head is not still cryogenically preserved, RIP Ted.

In perusing Pierre van der Walt's book I noted a highlighted passage.
He says John Rigby brought out the .45-2.4"-Match cartridge in 1870.
Done on a shortened .45 BPE 3-1/4", might have been with coiled brass case ?
Something to look into ...
Who did the .45-90-2.4" with drawn brass case first ?
John Rigby or Sharps ?

Who did the .45-90-2.4" with drawn brass case first ? "

I dunno , but glad they did! It is very effective across a broad range of bullet weights and animals.

Update on the progress of the Ruger Hawkeye African 458 WM, fired today with CEB BBW #13 450 grain monolithic solids.

The 2 powders used in today’s session were AA-2230 and Varget, because they had shown the greatest likelihood of reaching the target MV of 2300-2350 fps in the 23” barrel. All firing was from the bench, seated at 25 yds with rear peep sight. I continue to be pleasantly surprised at the accuracy of this barrel with the Ruger #1 barrel. Thanks to Sir Ron for the Varget suggestion - it works.

With AA-2230 MVs measured at about 10 yds uncorrected, 76.0 grains (MV = 2298 fps), 78.0 grains (MV = 2344 fps), 80.0 grains (MV = 2381 fps). Target MV achieved, accuracy excellent.

With Varget, using same bullet and MV measured at same distance 76.0 grains (MV = 2254 fps), 78.0 grains (MV = 2297 fps), 80.0 grains (MV = 2348 fps). I’ll probably use the AA-2230 load as it requires minimal compression to load 80 grains.

Small modification to the magazine box opening in the stock was the placement of a steel shim in front of the mag box backed by an aluminum spacer to prevent any movement of the box with recoil. Feeding is flawlessly smooth now, with a 375 H&H follower which locates the bullets very close to the centerline of the magazine.

I am ver pleased with the outcome of this rifle.

This is the 25 yd target showing the result of CEB BBW #13 450 grain bullet 2 shots with AA-2230 80.0 grains and 2 shots each with Varget 76.0 & 80.0 grains. 6 shots total with the Hawkeye African 458 WM.

Good to hear that is turning out well.

Yes, the .45-90 WCF used light bullets and slow twist.
Referring to the books, the 2.4" case was first produced by WRA Co. in 1884.
Offered in the M1885 High Wall single shot and then the M1886 lever action.
Cartridge was cataloged until 1913.
Jacketed bullets became available in 1892, in addition to the usual grease-grooved cast lead.
In 1895 both smokeless and BP loads were offered.
In 1903 Winchester High Velocity (WHV) in soft point, then in 1905 the Full Metal Patch (FMJ) arrived.
300-grain FN FMJ !!!
Great Britain used the M1886 with .45-90 WHV rounds to shoot down German observation balloons in WWI,
according to Giles & Shuey.
Heh-heh-heh.

Sharps Company, from Frank Sellers:
".45 CALIBRE 2.4-INCH STRAIGHT
While this cartridge is commonly called the '.45/90' by today's collectors,
the Sharps Company never loaded it with less than 100 grains of powder.
It was used exclusively as a target load in the Model 1874, Model 1877,
and Model 1878 Long-Range rifles. The cartridge was introduced on June 8, 1877.
The common load was in this was .45/100/550 paper patch."

Sharps had introduced the ".45 CALIBRE 2.6-INCH STRAIGHT" in November of 1876.
It used the same load, .45/100/550 paper patch.
Replaced by the 2.4" loaded with more of the bullet hanging out in the bore.
Throat did not matter since the paper-patched bullet was patched to bore diameter
and was smacked on the bottom by BP to obturate the rifling grooves.
IIRC, the old Sharps just had a 5-degree or 7-degree angle at the end of chamber neck, leading into the rifling.
Just a wide-based leade going abruptly into the rifling,
sort of like the cone on the front end of a shotgun chamber.
Heh-heh-heh.

OK, if John Rigby was doing a .45-2.4" in 1870, as van der Walt says,
it must have been a coiled brass and paper case.
Must have been one of those early experiments with that new-fangled central fire instead of rim fire.
I have found citations indicating that circa 1880 John Rigby was using both .45-2.4" and .45-2.6" drawn brass cases for his "Match" cartridges.
Must have been trying to keep up with the .461 Gibbs No. 1 and .461 Gibbs No. 2.
Keeping up with the Gibbses, heh-heh-heh.

The .45-2.4" has a rich history.
It obsoleted the .45-2.6" Sharps Straight
just like the .458 WM+ obsoletes the SAAMI .458 Lott.
Heh-heh-heh.