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

Mindful of minimizing paper waste, a previously small-bore-perforated target was used to get the bigger holes on paper:



No fooling of chronograph nor damage to sky screens by lube wads occurred with chrono placed at 7 to 8 yards.
Only 5 rounds were chronographed to minimize the risk.
570-grainer instrumental velocity mean = 1236 fps, with Sd = 7 fps for the 5 shots:







About the charitably-donated, paper-patched 555-grainers with patched diameter of only 0.448",
test-fired in the .45-2.6" SWT: 5 shots tried, 4 of 5 keyholed, only one made a round hole.
I pulled the remaining 5 to save for another trial in a "no-throat" .45-70 Govt. with .457" groove diameter.
Ditto my own 531-grainers which patched up to .449" diameter,
5 tried in the .45-2.6" SWT with Pedersoli barrel, only 2 made round holes. Goldie Ruger-Pedersoli was quite embarrassed by this.
In the .458 WM+ my 531-grain, paper-patched bullets keyholed 5 more.

I have concluded that for the long-throat with wide base,
if paper-patched and BP are used, the slick must be at least of bore diameter, and patched up to at least groove diameter.
I had good results previously using .452"-diam./ 530-gr. pure lead slick (bought from Buffalo Arms Co.) patched up to .459" diameter,
in a .459"-grooved, 22"-barreld (1:20" twist) .45-2.6"-SWT, made by re-chambering a factory Ruger No. 1 .45-70 Govt.



The five remaining 555-gr. paper-patched bullets will be held in trust for future expenditure when appropriate.
Buy a donkey, Sir Jerry.

The SAAMI .458 WM throat allows use of .461-caliber cast bullets loaded long.
I am convinced that, combined with PC paint, gas check and hard alloy, the .461" diameter is best in the common .459"-grooved .458 WM,
for top accuracy and velocity smokeless loads.
A .459"-diameter parallel-sided free-bore of whatever length requires fussing with bore-rider noses and other delicacies.
Consider the poor ol' .458 Lott.
The no-throat .45-70 Govt. might be better with paper-patched bullets,
or we just have to get fussy and patch our full-bore slicks to groove diameter in a .458 WM or .458 WM+ or .45-2.6" SWT.

A .458"-diameter right cylinder displaces 41.66 grains of water per inch of length/height.
If Bob loads his .45-70 LT 0.3" longer than his .45-70 Govt. load with a .458-caliber bullet,
he has added (0.3 X 41.66) = 12.50 grains of water in effective capacity.
H335 to fit in that extra space will weigh more than that since it is denser than water.

At that length of COL, Bob has reached the end of his throat in the .45-70 LT.
With the .45-70 LT+, using a .458 WM throat,
further effective case capacity increase as well as greater pressure let-off are possible.
With the excellent accuracy record of the SAAMI .458 WM, what is to lose ?

Since Buffalo Arms Co. sells .451"- to .452"-diameter, swaged-lead slicks of 530-gr. weight, I bet it is no secret that they work well in .458"- to .459"-grooved barrels.
BP or duplexed BP only, with paper patch, of course.

Here is the rifle that keyholed with sub-bore-diameter PP, 555-gr., 1:20 lead alloy:



Even with this lipstick on the pig:



Just laughing rather than crying about the spilt milk. Goldie Pedersoli-Ruger is no pig.
Her Chamber:



Here is the .459"-grooved, 1:20" twist, 22"-barreled .45-100-Sharps Winchester Throated (.45-2.6" SWT) that did better with
groove-diameter PP bullets and duplexed BP:



Lipstick on this piglet is a Nikon SlugHunter:



Here are the PP bullets used more successfully in the .458 Winchester Magnum throat of the .45-2.6" SWT:

Of course my .45-2.6" SWT is exactly the same as the C.I.P. homologated .45-70 Elko Magnum created decades before I thought I had invented something new.

I have only shot 10 paper-patched 530-gr BACO bullets in it with duplexed BP, getting over 1400 fps from the 22" barrel.



I wasted 20 more of them with smokeless, gaining nothing but unwanted velocity and worse accuracy:
35 grains of AA-5744 >>> 1255 fps
50 grains of AA-5744 >>> 1709 fps average of 5 shots and wild extreme spread of velocities !
Paper-patched bullets and AA-5744 mix like oil and vinegar.

So accounting for those 30 slicks out of a single box of 50, I have 20 more left.
This may allow Goldie Pedersoli-Ruger a chance to save face, maybe do better than her runt sister,
if loaded like Bobbee Boom-Boom Ruger had a fling with:



Correction: Above should read " ... powder compression may be reduced from 0.470" to 0.4315" ..."
by substituting a poker-card wad and a Cut-Rite wax paper wad for the two Circle Fly card wads.





That was the first 10 paper-patched bullets I ever fired in June 2019, 20 more wasted with AA-5744.
I fired 15 more on 4-14-2021, bringing my lifetime total to 45 fired in three different rifles:
Bobbee, Goldie, and Marcella, two single-shot rifles, and one bolt-action rifle.
This completes my latest audit of paper-patch bullet accounting.
Yes, one of my three degrees is a Bachelor of Science in Accounting, but I refused to memorize useless manmade crap for the CPA exam way back then.
Now you gotta have a master's degree to take such a crap !

Accurate Molds has these two interesting moulds for slicks that might work for paper patch bullets in the .458 WM throat.
If it works in the .45-2.6" SWT it will work in the .458 WM+ or .45-70 LT+:





Those diameters and weights are for WW alloy.
I would specify tolerances of -.000" / +.002" methinks.

The .458 Win Mag is great, until you actually shoot it and your shoulder taps out after one round fired!

Sir Ron;

Some clarification: I'm not 100% sure that the throat was extended by only 0.30". It may have been a bit more. I cite that number because that's what my gunsmith said, in his words (because I sent him some dummies): "How long do you want me to go, it's ABOUT .30" now." I told him that should be enough. I've never actually measured it. I simply wanted to be able to load the long bullets to 0.25" into the case without being jammed into the rifling, with a bit of "freebore". That worked for the 450 AF and 500 Hor. But later, I actually seated the 450 X-Bullet longer than 3.34" as in .458 WM without a hitch. I used 75 grains of H335 for the 500 and 75.5 for the 450... that's all i could get in without undue compression and still seat bullets to 0.25" If the throat had been 0.75", I still couldn't have loaded more H335, and the pressure would have been less with less MV.

In my CZ550 in .458 that came later, I used the extra "free bore" and long action to seat bullets "long", which was not strange to me as I'd done that with several rifles that permitted it. But to that point I'd been somewhat influenced by Finn Aagaard who had done a test of five rifles in .458 Win, including his own with a 23" barrel, using factory ammo from Federal, Winchester and Remington. These were 500s. The riffle that gave best results across the board in MV was his own semi-custom with a short throat and 23" barrel. For example: From the Federal 500gr he got 2188 fps from their 500, and he accounted it to the short throat, which he didn't previously know was in his new .458 barrel that had replaced the "finished" .423". He said the long throat was "a mistake". He also said he didn't experience any signs of "high pressure" from his rifle.

Of course, in a .458 with an action that permits it, seating bullets longer than SAAMI is the right way to go, as in my CZ or Ruger No.1 to take advantage of the chamber and leade. That's all been settled now and I'd want any .458 in my possession to have the "long throat" allowing more room for the best powders without undue PSI.

Not sure that clarifies anything... but maybe.

Bob
www.bigbores.ca

Not necessarily true; in my blog today I briefly touch on that subject, but it deserves more detail.

Bob
www.bigbores.ca

Sir Bob,

Your blog never disappoints, thanks.
Ruger4Life, though I applaud his handle and could use it for myself, was probably just yanking our chains, or he needs to read your blog.

You could have checked your throat length on the .45-70 LT by the slug and rod method.
From what you are saying, sounds like it was greater than 0.3" long X 0.459" diameter of parallel-sided free-bore.
Your gunsmith was as precise as Finn Aagaard's Kenyan gunsmith.

About Finn Aagaard saying the long throat of the .458 WM was a mistake, I remember that well and have the article where it happened.
IIRC, he said that one time in all his writings.
It is the only time I ever disagreed with Saint Finn, other than a few times wishing he would be more precise,
such as, for example, when he said most .458 WM rifles have 7/8" of free travel in the throat.
Minimum spec is for 0.6725" free travel if the bullet is 0.458" diameter at the case mouth of 2.500" brass, and if the bullet has an ogive of reducing diameters above that.
That free travel will be even less if the bullet is a full .458" diameter at any level beyond the case mouth, as most are.

When Finn Aagaard attributed over 100 fps of extra velocity to his custom barreled .458 WM of 23" barrel length and 1/8" free travel in throat,
he compared it to a 22"-barreled, pushfeed, factory M70,
and neglected to mention, immediately in that comparison, the longer-than-SAAMI-minimum throat of the 22-incher which he revealed elsewhere,
and neglected any differences in bore and groove and finish inside the barrels,
and neglected any pressure comparison except to say that he had never seen any indications of pressure problems in the field,
with any .458 WM he had owned.

It is well known that many times rifles thought to be identical in chamber and barrel specs may be 200 fps or more apart in MV with the same ammo.

I will dig up the articles that mention the .425 WR Mauser 98 that Finn Aagaard had custom barreled to .458 WM by a Kenyan gunsmith with a custom barrel and
unbeknowst to Finn Aagaard at the outset, a short throat, later discovered.
I am glad you agree that the SAAMI .458 WM throat was not a mistake.
The Lottite Cabal may have corrupted even Finn Aagaard, before the end of his earthly career.
That statement came late in his life.
However, I bet he recanted before his sainthood arrived.

I am having trouble finding certain powders for Hornady's listed loads for 300 JHP in 458 WinMag. Can I substitute loads for the 450 Marlin.

Specifically 50 grains RL-7 with 300 JHP with a goal of 2000 fps. Will I be safe and close to the money?

I used 60 grains of RL7 with the Hornady 300 JHP. I never shot them over a chrono but I believe I found the data in the Sierra manual.

Thank you beretzs. That boosts my confidence. What velocity did Sierra show in the manual for 60gr? OK, I am reading a little closer. You may not have that manual handy. If not, no problem. I was thinking to up the charge to 55 or if the book shows 2,000 with 60, then I would load that. At this point, I am splitting hairs. I will flip a coin

If the 300gr bullets are not accurate, then I may try something a little heavier. My limited experience is the biggest variable for accuracy is the bullet. I took a chance on 100 of these Hornady. These days, I am lucky to find anything for components.

The Sierra 6th Edition Reloading Manual lists, for 458 Win Mag, 300 gr flat nose (Sierra #8900), COAL 2.930":

RE-7 60.9gr - 2200 FPS
63.7gr - 2300 FPS
66.5gr - 2400 FPS [max]

Hi Ron, glad you made it over. I have a question. I have a spare Win 70 stainless in 338 WM I’d like to rebarrel into 458. Any suggestions on who can do the work? I’d like it fairly light 21-22” NECG sights and cerakote it. Any thoughts?
Regards
S

I would look to 3031 powder if you have any, slow that hp to around 1800 fps if you can safely do so, it'll still shoot plenty flat and penetrate better woed up a bit, it should shoot really well in the Great 458 Win Mag.

Good stuff Sir Ron, hope those missiles i sent weren't too long, they did punch nice round holes, getting good hunting accuracy while shooting dirty is half the fun.

Hanny,

That is great info. Thank you. I loaded up my first 20 rounds using 56 grains RL7. That should be plenty fast for 300gr hollow points. Tomorrow's weather looks promising for a day at the club.

Gunner 500,

I do have some 3031. Although, I kinda holding whats left that for my 303 Brit. If you have a pet load for 1800fps. Let me know and I will put that in the margins along with the RL7 info.

My local smith is backed up and I could not recommend you send something from Idaho to Kentucky right now.
Unless Charlie Sisk would take on something so simple, yet so worthy ...

fourbore,

You should do well with that.
In Ken Waters Pet Loads, he has over 60 loads listed for his .458 WMs, a 24" Ruger No.1 and a 22" Winchester M70.
Under "Reduced Loads," all with W-W brass and W-120 primer in the 24" Ruger No. 1:

300-gr Sierra HP
55.0 grains of Re-7, COL 3.00" >>> 2,026 fps "SECOND MOST ACCURATE LOAD" (Out of 61 loads Waters commented on.)
60.0 grains of IMR-3031, COL 3.00" >>> 1,902 fps

300-gr Hornady HP
58.0 grains of Re-7, COL 2.99" >>> 2,062 fps "GOOD LOAD"

And not so reduced:
350-gr Hornady RN
72.0 grains Re-7, COL 3.05" >>> 2,194 fps "ONE OF TWO BEST ALL-AROUND LOADS; MOST ACCURATE LOAD TESTED"

(The 300-gr Sierra HP has been known to vaporize within 25 yards of muzzle when traveling over 2800 fps MV.
Ask me how I know.
I actually fired a second one and it vaporized inside the muzzle brake. I was using AA-1680 ...)

The Barnes TSX and TTSX are recommended for velocities over 2500 fps with 300-grainer, ho, ho.
1800 to 2100 fps is plenty with those 300-gr HPs from Sierra and Hornady.

I would not hesitate to use some filler for the reduced loads above, like foam wad filler (caulk backer rod). Waters used kapok wads in his cast bullet loads:

"Kapok wads weighing 3/4-grain, tamped down lightly on the powder, helped materially but proved insufficient to allow any major increase in velocities ..."

The Barnes monometals can be loaded all the way up to Obi Wan Bob levels if you like.
Maybe I'll make it to +3000 fps with the Hornady 250-gr Monoflex one of these days.