458 Win Mag for deer and bear

[cajunchefray]

Thank for the info. I might have some 5744, got to look. What cast bullet are you using?
Looking forward to your report.

I’m using Oregon Trail Laser cast 405 grain FP. I’m looking for some powder coated 350 grain FP.

It will be a couple of weeks, I’ll let you know.

 

[jnmullins]

The cast bullets I’ve got are from a Lee 457-500-F, that come out of the mold measuring around .459 and right on weight. I’ve tried 36.0 gr AA5744, but I’m not sure of the velocity because my chronograph didn’t pick them up. I’m going to load up a few more and trying them again, plus some with increasing powder charges.

Here is the excerpt from the Lyman manual that I used. Note that the data is for 475gr and I’m working up for a 500gr.

 

[Inkgardener]

I like IMR 4198 in my cast bullet rifle loads. I would use that or a reduced load of H4895. Hodgdon lists reduced loads for that powder.

 

[Riflecrank]

I started cast bullet shooting of the .458 WIN MAG with a Whitworth Mark X also.
23.6"/600mm factory barrel length.

First up was the "store-bought" 409-gr/.459" Berry's HardCast RNFP meant for .45-70.
3.080" COL .458 WIN MAG:
26.0 gr AA-5744 >>> 1182 fps MV and 1.2 MOA for 3 shots
30.0 gr AA-5744 >>> 1376 fps MV and 1.4 MOA for 3 shots

Next up was home-made by me, 485-gr/.459" Lyman RNFP-GC
3.108" COL
26.0 gr AA-5744 >>> 1168 fps MV and 1.4 MOA for 3 shots
30.0 gr AA-5744 >>> 1342 fps MV and 1.4 MOA for 3 shots

Use Magnum primer like F-215 or WLMR/WMR or CCI-250 or etc.
No filler needed.
Any powder charges greater than those above and the bullets would keyhole and groups became shotgun patterns.

Eventually I learned that the .458 WIN MAG with SAAMI throat needs treatment different than the no-throat .45-70 with slower twist and tighter groove diameter.

0.459" bullets work best in .456" to .457" groove diameter
whether grease-grooved or powder-coat-painted, plain-base or gas-checked, soft or hard alloy, and slower velocity is more usual with the .45-70 as are the usual twist rates slower.

Never fear, the 0.458" to 0.459" groove diameter and 1:14" twist of the .458 WIN MAG
is very capable with cast bullets.

Make them 0.461" diameter of hard alloy.
Mine cast at 0.463" and when passed through a 0.460" base-pusher sizer they spring back to 0.461".
LEE or CH4D sizers work equally well.
Powder-Coat paint them before sizing and you can install the gas check as you push them through the sizer.

I use an alloy I call BHN25, having a BH number of 24.8.
It is harder and heavier than Linotype, casts to same size, and is not brittle like Linotype.
It can also be heat treated due to small amount of arsenic in it.
It naturally ages back to its water-dropped hardness of 24.8 BHN.

No lead fouling:

I too like Accurate Molds moulds for most casting of lead bullets.

I like the 2-cavity brass moulds from Accurate Molds.
My two favorite bullets are each on one side of a two-cavity:

Bullets made like detailed above will respond to handloading like any jacketed or monometal bullet,
accurate up to about 2200 fps for 400-gr to 600-gr weights in the .458 WIN MAG.
I have been too busy with monometal copper and brass 400-ish gr bullets lately at +2500 fps in the 458 WIN MAG.
But I reckon my cast loads will kill well on "deer and bear."
I did one water impact at 2200 fps with a 410-gr/.396" LBT LFN from a wildcat and got a beautiful mushroom.

 

[cajunchefray]

I started cast bullet shooting of the .458 WIN MAG with a Whitworth Mark X also.
23.6"/600mm factory barrel length.

First up was the "store-bought" 409-gr/.459" Berry's HardCast RNFP meant for .45-70.
3.080" COL .458 WIN MAG:
26.0 gr AA-5744 >>> 1182 fps MV and 1.2 MOA for 3 shots
30.0 gr AA-5744 >>> 1376 fps MV and 1.4 MOA for 3 shots

Next up was home-made by me, 485-gr/.459" Lyman RNFP-GC
3.108" COL
26.0 gr AA-5744 >>> 1168 fps MV and 1.4 MOA for 3 shots
30.0 gr AA-5744 >>> 1342 fps MV and 1.4 MOA for 3 shots

Use Magnum primer like F-215 or WLMR/WMR or CCI-250 or etc.
No filler needed.
Any powder charges greater than those above and the bullets would keyhole and groups became shotgun patterns.

Eventually I learned that the .458 WIN MAG with SAAMI throat needs treatment different than the no-throat .45-70 with slower twist and tighter groove diameter.

0.459" bullets work best in .456" to .457" groove diameter
whether grease-grooved or powder-coat-painted, plain-base or gas-checked, soft or hard alloy, and slower velocity is more usual with the .45-70 as are the usual twist rates slower.

Never fear, the 0.458" to 0.459" groove diameter and 1:14" twist of the .458 WIN MAG
is very capable with cast bullets.

View attachment 702405

Make them 0.461" diameter of hard alloy.
Mine cast at 0.463" and when passed through a 0.460" base-pusher sizer they spring back to 0.461".
LEE or CH4D sizers work equally well.
Powder-Coat paint them before sizing and you can install the gas check as you push them through the sizer.

I use an alloy I call BHN25, having a BH number of 24.8.
It is harder and heavier than Linotype, casts to same size, and is not brittle like Linotype.
It can also be heat treated due to small amount of arsenic in it.
It naturally ages back to its water-dropped hardness of 24.8 BHN.

No lead fouling:

View attachment 702406

I too like Accurate Molds moulds for most casting of lead bullets.

View attachment 702407

View attachment 702409

View attachment 702408
I like the 2-cavity brass moulds from Accurate Molds.
My two favorite bullets are each on one side of a two-cavity:

View attachment 702410
View attachment 702411View attachment 702412
Bullets made like detailed above will respond to handloading like any jacketed or monometal bullet,
accurate up to about 2200 fps for 400-gr to 600-gr weights in the .458 WIN MAG.
I have been too busy with monometal copper and brass 400-ish gr bullets lately at +2500 fps in the 458 WIN MAG.
But I reckon my cast loads will kill well on "deer and bear."
I did one water impact at 2200 fps with a 410-gr/.396" LBT LFN from a wildcat and got a beautiful mushroom.

Like the name 458 Light Express Load for the 407-grain bullet.
The .002 to .003 over the nominal bullet diameter reminds me of load development done by Mike Venturino, Brian Pearce, Elmer Keith and others for revolvers, especially the early Colt SAA .45 colt models.
Slightly oversized cast bullets of proper alloys to snjug up from the chamber to barrel, good gas seal consistent velocity.

I don't cast bullets (yet), but can you share your BNH 25 alloy formula?

I currently don't have arsenic in stock (it was kindly and gently removed by Louisiana DEQ from our cotton farming operations).

Perhaps another Non-Chinese source? Or rare Earth Metals?
I'm not averse to thinking outside the conventional metallurgy box.

@Riflecrank, always appreciate your detailed, engineer approach data for the .458 Win Mag. Everybody needs to own at least one.

 

[Riflecrank]

Like the name 458 Light Express Load for the 407-grain bullet.
The .002 to .003 over the nominal bullet diameter reminds me of load development done by Mike Venturino, Brian Pearce, Elmer Keith and others for revolvers, especially the early Colt SAA .45 colt models.
Slightly oversized cast bullets of proper alloys to snjug up from the chamber to barrel, good gas seal consistent velocity.

I don't cast bullets (yet), but can you share your BNH 25 alloy formula?

I currently don't have arsenic in stock (it was kindly and gently removed by Louisiana DEQ from our cotton farming operations).

Perhaps another Non-Chinese source? Or rare Earth Metals?
I'm not averse to thinking outside the conventional metallurgy box.

@Riflecrank, always appreciate your detailed, engineer approach data for the .458 Win Mag. Everybody needs to own at least one.

Thank you cajunchefray for the interest,

My recipe for 10.5 pounds of BHN25 is based on only two ingredients.

1. Lawrence Brand Magnum Shot size 7-1/2 (best all purpose for squirrels and such).
My research indicated it contains 5% antimony and 1.25% arsenic and the remainder is lead.

2. 50:50 Solder with equal parts/weights of tin and lead.

Mix 10 pounds of the shot with
a half-pound of the solder,
stirring well as you add small quantities of each to the pot. Snip the solder wire into small pieces to drop in the pot with the shot as you pour in the shot and stir. Stirred not shaken.

Approximate composition of BHN25 Alloy:
91.90% Pb (lead)
4.76% Sb (antimony)
2.38% Sn (tin)
0.95% As (arsenic)

Roughly the percentages are: 92/5/2/1
So "92/5/2/1 Alloy" is an aka for BHN25.

Water drop from mould into a 5-gallon bucket of room-temperature water: BHN 24.8 to stay.
PC-painting them in an oven at about 375*F for a half hour will soften them to BHN 21.8.
They will age back to 24.8 BHN in two weeks of sitting at room temperature.
That is what I found out by trying it out myself.
The recipe is hereby released to the gun trade, again.

 

[Riflecrank]

I can't short change the heavy bullet at low velocity, "Big Blue":

3 shots land a little low at 200 yards, but that would be a real buffalo killer in the 1870s with a Soule sight.

The Heavy Rifle Express load with this bullet would be wonderful at 2150 fps MV from a .458 WIN MAGA.
Bullet integrity would probably be better than this:

Bears are not heavy boned. Might do well for big bears.
Remember the .458 Lott throat diameter is so tight and short that this bullet would be a poor choice in the .458 Lott,
as would be some other heavies that I load to 3.600" COL in the .458 WIN MAGA:

That 543-gr/.461" FN GC loaded with 75.0 grains of AA-2460, 3.600" COL gave 2190 fps from a 25" barrel, for three shots into 1" at 50 yards.
78 grains AA-2460 gave 2265 fps and 3 shots into about 1.5" at 50 yards.
Not bad.
75 grains of AA-2460 was an 89% LR/net fill at 3.600" COL.
78 grains of AA-2460 was a 93% LR/net fill at 3.600" COL
78 grains of H4895 was a 103% LR/net fill (mildly compressed) at 3.600" COL with the 543-gr FN GC.

Cast Bullets shoot better in a .458 WIN MAG than a .458 Lott.

 

[1dirthawker]

@Brickman301,

i have an interarms 458 win. i just finished loading some 404gr hammer bullets for it. i am using H4895, getting 2425 fps. my intentions are to use it as backup for brown bear (guiding) and i am gonna go to kodiak after and shoot some blackmails with it. (use enough gun)

is AA2640 is a little faster burning? i have tried up to 76 gas of 4895 got to 2450 fps. about ran out of case space, and that is with a 24" drop tube. 2425 fps is still 416 rigby velocity, i suspect it will kill a bear or deer.

interesting thread.

 

[Riflecrank]

My Kodiak "blackmails" were taken with 340 WBY and 375 WBY rifles.
The 458 WIN MAG would be an even better Kodiak Deer Rifle using that 404-gr Hammer bullet.
Yes AA-2460 is faster and more compact in the case than H4895.

 

[1dirthawker]

@Riflecrank,
stupid auto correct. by the time i saw it, couldn't edit.

is AA-2460 also a low pressure powder in the 458? h4895 is very much so. i am limited by the box length as well, i am getting 3.280" COAL to get it in the magazine box, seating out as many have noted would help a lot, but i am kinda stuck there. i could go a few grains more and get 2500 fps i am sure, but bullets are touching/overlapping at 2424 fps so......i stopped.

should be fun hunt off a 65' boat with 2 other guides (good friends) on the boat. king crab, halibut and deer hunting, should be a great time. i gotta stop hijacking thread tho, this is about the 458.

i even put nail polish around the primer pocket for the brass that a couple of generous AH members sent to me. got a funny look from my wife tho.

 

[cajunchefray]

I got a funny look and questions from my wife when I uses nail polish (hot pink), while testing COAL, painted on the bullets to measure the throat of my 458 Whitworth.
I had to show her my procedure finding the length to the lands and how it works, for her to stop asking me What's her name?

We laugh about it now.

 

[cajunchefray]

I can't short change the heavy bullet at low velocity, "Big Blue":

View attachment 702415View attachment 702416

3 shots land a little low at 200 yards, but that would be a real buffalo killer in the 1870s with a Soule sight.

View attachment 702417

The Heavy Rifle Express load with this bullet would be wonderful at 2150 fps MV from a .458 WIN MAGA.
Bullet integrity would probably be better than this:

View attachment 702418
Bears are not heavy boned. Might do well for big bears.
Remember the .458 Lott throat diameter is so tight and short that this bullet would be a poor choice in the .458 Lott,
as would be some other heavies that I load to 3.600" COL in the .458 WIN MAGA:View attachment 702419

That 543-gr/.461" FN GC loaded with 75.0 grains of AA-2460, 3.600" COL gave 2190 fps from a 25" barrel, for three shots into 1" at 50 yards.
78 grains AA-2460 gave 2265 fps and 3 shots into about 1.5" at 50 yards.
Not bad.
75 grains of AA-2460 was an 89% LR/net fill at 3.600" COL.
78 grains of AA-2460 was a 93% LR/net fill at 3.600" COL
78 grains of H4895 was a 103% LR/net fill (mildly compressed) at 3.600" COL with the 543-gr FN GC.View attachment 702420View attachment 702421View attachment 702422View attachment 702423
Cast Bullets shoot better in a .458 WIN MAG than a .458 Lott.

Thank you cajunchefray for the interest,

My recipe for 10.5 pounds of BHN25 is based on only two ingredients.

1. Lawrence Brand Magnum Shot size 7-1/2 (best all purpose for squirrels and such).
My research indicated it contains 5% antimony and 1.25% arsenic and the remainder is lead.

2. 50:50 Solder with equal parts/weights of tin and lead.

Mix 10 pounds of the shot with
a half-pound of the solder,
stirring well as you add small quantities of each to the pot. Snip the solder wire into small pieces to drop in the pot with the shot as you pour in the shot and stir. Stirred not shaken.

Approximate composition of BHN25 Alloy:
91.90% Pb (lead)
4.76% Sb (antimony)
2.38% Sn (tin)
0.95% As (arsenic)

Roughly the percentages are: 92/5/2/1
So "92/5/2/1 Alloy" is an aka for BHN25.

Water drop from mould into a 5-gallon bucket of room-temperature water: BHN 24.8 to stay.
PC-painting them in an oven at about 375*F for a half hour will soften them to BHN 21.8.
They will age back to 24.8 BHN in two weeks of sitting at room temperature.
That is what I found out by trying it out myself.
The recipe is hereby released to the gun trade, again.

@Riflecrank, thanks very much for the formula and procedure. Formulas, procedures and sourcing ingredients is my life's work in food production. Your post makes total sense.

Where do you source Arsenic?

I found some from Fisher (Thermo) Scientific, and a couple of other sites.
Need a statement on Company letterhead or academic research. No problem I can handle that.

What is your preferred no hassle source?

 

[cajunchefray]

I should have reread all of your post; I was too focused on the chemical formula.

Lawrence magnum 7.5 shot and 50/50 solder. I'll find that.

Shopping now for a casting pot and bullet molds.
Thanks, your posts are informative. I have learned how to reload for my 458 Whitworth to longer COAL for better performance.

 

[Hyde Hunter]

I plan to hunt with my 458 this fall using full power 420gr CEB Raptors or 450gr TSX. I’ll shoot a deer if one comes by, but I’m also quite curious what these bullets do to a big hog, especially if two or more line up

well I can tell you they will turn a hog inside out. I have shot 2 cape buffalo with the 420 CEB's at 2450FPS and they went through both buffalo and are probably still going. the 370 Raptor would be good for them

 

[Hyde Hunter]

@Brickman301,

i have an interarms 458 win. i just finished loading some 404gr hammer bullets for it. i am using H4895, getting 2425 fps. my intentions are to use it as backup for brown bear (guiding) and i am gonna go to kodiak after and shoot some blackmails with it. (use enough gun)

is AA2640 is a little faster burning? i have tried up to 76 gas of 4895 got to 2450 fps. about ran out of case space, and that is with a 24" drop tube. 2425 fps is still 416 rigby velocity, i suspect it will kill a bear or deer.

interesting thread.

I run 80 grains of AA2230 and a fed 215 primer with then 404 Stone Hammer with an 19" barrel CZ550 and get close to 2500 fps

 

[Brickman301]

I started cast bullet shooting of the .458 WIN MAG with a Whitworth Mark X also.
23.6"/600mm factory barrel length.

First up was the "store-bought" 409-gr/.459" Berry's HardCast RNFP meant for .45-70.
3.080" COL .458 WIN MAG:
26.0 gr AA-5744 >>> 1182 fps MV and 1.2 MOA for 3 shots
30.0 gr AA-5744 >>> 1376 fps MV and 1.4 MOA for 3 shots

Next up was home-made by me, 485-gr/.459" Lyman RNFP-GC
3.108" COL
26.0 gr AA-5744 >>> 1168 fps MV and 1.4 MOA for 3 shots
30.0 gr AA-5744 >>> 1342 fps MV and 1.4 MOA for 3 shots

Use Magnum primer like F-215 or WLMR/WMR or CCI-250 or etc.
No filler needed.
Any powder charges greater than those above and the bullets would keyhole and groups became shotgun patterns.

Eventually I learned that the .458 WIN MAG with SAAMI throat needs treatment different than the no-throat .45-70 with slower twist and tighter groove diameter.

0.459" bullets work best in .456" to .457" groove diameter
whether grease-grooved or powder-coat-painted, plain-base or gas-checked, soft or hard alloy, and slower velocity is more usual with the .45-70 as are the usual twist rates slower.

Never fear, the 0.458" to 0.459" groove diameter and 1:14" twist of the .458 WIN MAG
is very capable with cast bullets.

View attachment 702405

Make them 0.461" diameter of hard alloy.
Mine cast at 0.463" and when passed through a 0.460" base-pusher sizer they spring back to 0.461".
LEE or CH4D sizers work equally well.
Powder-Coat paint them before sizing and you can install the gas check as you push them through the sizer.

I use an alloy I call BHN25, having a BH number of 24.8.
It is harder and heavier than Linotype, casts to same size, and is not brittle like Linotype.
It can also be heat treated due to small amount of arsenic in it.
It naturally ages back to its water-dropped hardness of 24.8 BHN.

No lead fouling:

View attachment 702406

I too like Accurate Molds moulds for most casting of lead bullets.

View attachment 702407

View attachment 702409

View attachment 702408
I like the 2-cavity brass moulds from Accurate Molds.
My two favorite bullets are each on one side of a two-cavity:

View attachment 702410
View attachment 702411View attachment 702412
Bullets made like detailed above will respond to handloading like any jacketed or monometal bullet,
accurate up to about 2200 fps for 400-gr to 600-gr weights in the .458 WIN MAG.
I have been too busy with monometal copper and brass 400-ish gr bullets lately at +2500 fps in the 458 WIN MAG.
But I reckon my cast loads will kill well on "deer and bear."
I did one water impact at 2200 fps with a 410-gr/.396" LBT LFN from a wildcat and got a beautiful mushroom.

Thank you cajunchefray for the interest,

My recipe for 10.5 pounds of BHN25 is based on only two ingredients.

1. Lawrence Brand Magnum Shot size 7-1/2 (best all purpose for squirrels and such).
My research indicated it contains 5% antimony and 1.25% arsenic and the remainder is lead.

2. 50:50 Solder with equal parts/weights of tin and lead.

Mix 10 pounds of the shot with
a half-pound of the solder,
stirring well as you add small quantities of each to the pot. Snip the solder wire into small pieces to drop in the pot with the shot as you pour in the shot and stir. Stirred not shaken.

Approximate composition of BHN25 Alloy:
91.90% Pb (lead)
4.76% Sb (antimony)
2.38% Sn (tin)
0.95% As (arsenic)

Roughly the percentages are: 92/5/2/1
So "92/5/2/1 Alloy" is an aka for BHN25.

Water drop from mould into a 5-gallon bucket of room-temperature water: BHN 24.8 to stay.
PC-painting them in an oven at about 375*F for a half hour will soften them to BHN 21.8.
They will age back to 24.8 BHN in two weeks of sitting at room temperature.
That is what I found out by trying it out myself.
The recipe is hereby released to the gun trade, again.

I can't short change the heavy bullet at low velocity, "Big Blue":

View attachment 702415View attachment 702416

3 shots land a little low at 200 yards, but that would be a real buffalo killer in the 1870s with a Soule sight.

View attachment 702417

The Heavy Rifle Express load with this bullet would be wonderful at 2150 fps MV from a .458 WIN MAGA.
Bullet integrity would probably be better than this:

View attachment 702418
Bears are not heavy boned. Might do well for big bears.
Remember the .458 Lott throat diameter is so tight and short that this bullet would be a poor choice in the .458 Lott,
as would be some other heavies that I load to 3.600" COL in the .458 WIN MAGA:View attachment 702419

That 543-gr/.461" FN GC loaded with 75.0 grains of AA-2460, 3.600" COL gave 2190 fps from a 25" barrel, for three shots into 1" at 50 yards.
78 grains AA-2460 gave 2265 fps and 3 shots into about 1.5" at 50 yards.
Not bad.
75 grains of AA-2460 was an 89% LR/net fill at 3.600" COL.
78 grains of AA-2460 was a 93% LR/net fill at 3.600" COL
78 grains of H4895 was a 103% LR/net fill (mildly compressed) at 3.600" COL with the 543-gr FN GC.View attachment 702420View attachment 702421View attachment 702422View attachment 702423
Cast Bullets shoot better in a .458 WIN MAG than a .458 Lott.

Super helpful and informative posts! This is great info! I’m new to the 458 Winchester.
I’ve been casting and loading for 45-70 for years. My hunting load is a Lyman “Gould” hollow point bullet. I cast it in pure lead, then powder coat it and it weights 344 grains. I use 47.5 grains of IMR3031.
I’ve had spectacular results with this load on deer.

I will use some of this info when I start loading for my rifle. I’m waiting till it cools off, it’s just too hot right now to stand around a lead pot!!

 

[Brickman301]

@Brickman301,

i have an interarms 458 win. i just finished loading some 404gr hammer bullets for it. i am using H4895, getting 2425 fps. my intentions are to use it as backup for brown bear (guiding) and i am gonna go to kodiak after and shoot some blackmails with it. (use enough gun)

is AA2640 is a little faster burning? i have tried up to 76 gas of 4895 got to 2450 fps. about ran out of case space, and that is with a 24" drop tube. 2425 fps is still 416 rigby velocity, i suspect it will kill a bear or deer.

interesting thread.

Thanks for the info!
I do have H4895 on hand, as I use it for several other cartridges I load for. Looks like I need to pick up some AA2640, as several here have recommended it.
404 grains @ 2425fps, now that’s impressive! I’m sure it will take down anything.

 

[Riflecrank]

1dirthawker,
3.28" COL with the 404-gr Stone Hammer will work fine.

If 76 grains of H4895 gets you to 2450 fps in your 23.6"/600mm nominal 24" barrel,
try same amount of either AA-2230 or AA-2460 to get to 2500 fps.
No drop tube needed for that.

Working up to Benchmark charge of 76.0 grains might be tops at 3.28" COL with "standard" brass cases:
W-W, R-P, Federal, Hornady.
I bet that will get you past 2500 fps MV,
with short COL in standard brass.
Benchmark is a faster powder than any of those above, and with its smaller extruded grains than H4895 it will take up less space in the case than H4895.

Using the larger case capacity Norma-made brass case will make your 3.280" COL
like a 3.380" COL with the smaller, "standard" brass cases.

 

[cajunchefray]

1dirthawker,
3.28" COL with the 404-gr Stone Hammer will work fine.

If 76 grains of H4895 gets you to 2450 fps in your 23.6"/600mm nominal 24" barrel,
try same amount of either AA-2230 or AA-2460 to get to 2500 fps.
No drop tube needed for that.

Working up to Benchmark charge of 76.0 grains might be tops at 3.28" COL with "standard" brass cases:
W-W, R-P, Federal, Hornady.
I bet that will get you past 2500 fps MV,
with short COL in standard brass.
Benchmark is a faster powder than any of those above, and with its smaller extruded grains than H4895 it will take up less space in the case than H4895.

Using the larger case capacity Norma-made brass case will make your 3.280" COL
like a 3.380" COL with the smaller, "standard" brass cases.

Looking up Stone Hammer bullets and other Hammer bullets, (their website is very informative, especially about faster twists rates, which I learned from Pierre van der Walt). they seem to be an improvement on the Barnes TSX, et al clan.

Mono metal bullets are new to me in use (I know, I'm behind the times).
What makes Stone bullets better?
Metallurgy, shape, design etc.?

Thank you @Riflecrank,

 

[Riflecrank]

Another thought:

Yep, I am the one that goaded Hammer into making this bullet.
It is patterned after the 270-gr/.375 SH that Fordy goaded up.
Average weight for this .458 is closer to 403 grains, but it was subsequently called the 404-gr Shock Hammer, then became the 404-gr/.458 Stone Hammer due to some copyright issue IIRC.

Above is the 3.280" COL using a standard capacity case, Hornady, with the 404-gr SH and F-215 primer.
In a 24"-barreled .458 WIN MAG, to get 2500 fps with H4895,
use long drop tube and whatever compression is required with H4895.
To put my money where my thinking is, I am going to do a test load of same.
I am going straight to 78.0 grains of H4895 as my starting load in a 24"-barreled Ruger No. 1 that I call Daisy.

I have done worse.
If you take a 2.500"-long Hornady .458 WIN MAG case and fill it to the top with loosely scooped H4895, it will hold 83.0 grains of H4895.
I then used a 26"-long, aluminum arrow shaft drop-tube and 87.0 grains left a little room for me to start seating a bullet.
That bullet was a 400-gr Woodleigh PPSN.
Bullet Overall Length = 1.155"
Seating depth = 0.230"
COL = 3.425"
MV = 2627 fps
corrected from 5-yard chrono for G1 BC = 0.340, 87* F,
from a 25" Shilen-barreled (1:14" twist) CZ 550 Magnum.

I figure that was about 110% compression after drop-tube fill.
Secondary cannelure was placed for even shorter seating than indicated on the unmolested bullet pictured above.
No excessive pressure signs due to the SAAMI .458 WIN MAG throat which is above the paygrade of QuickLOAD.
24"-barrel MV should be about 2612 fps.

87 grains was my starting load. I worked down from there.
Hard to get too much pressure with H4895 in a .458 WIN MAG and a 400- or 404-gr bullet.
2500 fps is the maximum impact velocity recommended with the Woodleigh 400-gr pancakers.
The 404-gr Stone Hammer is a much longer bullet, but 78.0 grains will give a lot more room than 87.0 grains of H4895, to start the compressing.

I will let Y'all know how I do seating a 404-gr Stone Hammer over 78.0 of H4895 in a Hornady case
to 3.280" COL,
and how Daisy likes it.
I have a Garmin now, no MV correction required.

The only time I had a primer fall out of a .458 WIN MAG case was with 86.0 grains of AA-2230 behind a 450-gr TSX, in a NORMA case of all things !
That was an excessive load for sure. Should have stopped at 84.0 grains where MV was 2464 fps in the 24" barrel of Daisy.
It was a never-before fired NORMA case.
I like once-fired and FL resized cases for the record.