Cast bullets in .458 Win Mag

fellers88

fellers88

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Alright friends i know this subject had been touched on a few times but i have not been able to come up with a solution using the search function on this site. I am trying to come up with a cast bullet load for my 458 win mag (zastava) and am having no luck in finding a load that is even remotely consistent. It cloverleafs hornady 300gr HPs over 3031 and 500gr over H335 but here is what i have tried with zero success... open to any suggestions as to what i should try next

Bullet barn 350 FN 3LG (no gas check)
3031 45gr with filler
Trail Boss 22gr

Bullet barn Postell 525 gr (no gas check)
3031 42gr with filler
Trail Boss 21 gr

I have also tried high pressure loads with these bullets just for funzzies with no real expectations because if i want to do full power loads I'll just use a jacketed bullet. So i guess what I'm saying is im looking for a 45-70 type load to shoot. Also i am using the expanding die to prevent shaving of the cast bullets, i tried only partial sizing to prevent that even more but i have not slugged my bore yet to see if i need larger diameter projectiles. The bullet barn projectiles are .458.5-.459 in diameter.
Thanks in advance
 
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Found a good load for my 458. Bullet Barn 525gr postell, CCI-BR primer, 26.6 grains ATK 2400. 1150 fps with great accuracy. 1200 fps is too much for these bevel based bullets. Rifle is a 98 Mauser with an RKS no-taper barrel.
 
I've got a plinking load for my .458. A RCBS flat base flat point that is nominally 500 grains but drops at about 535 grs with wheel weights. I shoot them un-sized and tumble lubed in liquid Alox with 25 grains of SR4759. Push them harder and accuracy goes to pot. Its not like there was a lot of load development involved. Started at 20 and went up 5 grains at a time to 30 and backed off 5.;) Does that make me a bad person?

 
fellers88 said:
Do you use a filler with that small a charge? I tried using backer rod cut to the size i needed but I'm pretty sure it wasn't fully consumed by the burn.
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No filler used with 26.6 gr 2400 under a 525 postell. Tipped loaded rifle barrel straight up and down and compered velocities of each, found no difference.
 
Interesting. The closest thing i have to 2400 and 4759 is IMR 4227, maybe I'll have to try that. Ill try with no filler using the 525gr boolit. What are your rifles twist rates?
 
I have a Zastava M70 .458 winmag too. I did not have any success using any 45-70 bullets. The postell bullet was almost tolerable but not anything to brag about. Then I got some 485gr cast bullets designed for 458 winmag and they worked better. Loading them at 1850 fps with IMR4198 is quite pleasant, more a shove than a punch.
 
Jethunter - I too have the same 458 Win Mag rifle. I am curious if you could clarify about those 485 grain cast bullets - you say they are designed for 458 win mag - what makes them different than other .458 cast bullets? Where can I get that mold?
 
Potashminer said:
Jethunter - I too have the same 458 Win Mag rifle. I am curious if you could clarify about those 485 grain cast bullets - you say they are designed for 458 win mag - what makes them different than other .458 cast bullets? Where can I get that mold?
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45-70 bullets are short, 458 bullets aren't. If the bullet has to jump a longer distance before it gets to the throat it won't usually be as accurate.

Bullets that are made for a .458 winmag chamber will have the crimp groove positioned so that the bullet is seated further out of the case. These bullets wouldn't chamber in a 45-70 because the OAL would be too long, but they fill up a 458 chamber very nicely and therefore have a much shorter jump to the rifling. They shoot better for that reason.
 
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Who manufactures these bullets? Ill have to try them out. If they work i may have a good bunch of bullet barn projectiles to sell off. Btw i slugged my bore tonight and itcame up consistently at .458 so no suprises there
 
fellers88 said:
Who manufactures these bullets? Ill have to try them out. If they work i may have a good bunch of bullet barn projectiles to sell off. Btw i slugged my bore tonight and itcame up consistently at .458 so no suprises there
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My Zastava is .458" groove diameter. It has fairly tight throat as well, a .459" bullet won't push back into a fired case.
 
Interesting comments - I shoot a 425gr Saeco spire point bullet designed for 458 Win. in my 45 70 rolling block with 25gr of 2400 powder and am very happy with the accuracy. The best - perfect conditions several years ago when my eyes were better - 4 5 shot groups averaged under 1" at 100yds with iron sights. Once in practice, once in the CBA's big bore bench rest postal. So - if you're shooting bolt action rifles, why aren't you seating the bullets out further to shorten the "jump"?

Grouch
 
grouch said:
Interesting comments - I shoot a 425gr Saeco spire point bullet designed for 458 Win. in my 45 70 rolling block with 25gr of 2400 powder and am very happy with the accuracy. The best - perfect conditions several years ago when my eyes were better - 4 5 shot groups averaged under 1" at 100yds with iron sights. Once in practice, once in the CBA's big bore bench rest postal. So - if you're shooting bolt action rifles, why aren't you seating the bullets out further to shorten the "jump"?

Grouch
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It's been awhile since I tinkered with my Zastava, but if IIRC, these rifles have quite the freebore. I may not be exaggerating when I say some bullets could be seated flush with the case mouth, and not bump the rifling.
 
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Dogleg said:
Some feel that the long free-bore has a lot to do with low velocities.
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How does longer freebore cause low velocities, and who feels that way?

I have always thought that more freebore was conducive to increased velocity but poorer accuracy. Weatherby has for decades used longer freebore to safely increase velocity potential of their rifles.
 
The poor accuracy with long freebore is rumored to be a proven fact by the Sharps rilfle built while they were still being made at Farmindale, N Y before the move to Big Timber, Mont. It took a concerted effort by BPCR shooters to convince Shilo to shorten up the freebore but once they did, it has proven a sound change and they never went back.
 
jethunter said:
How does longer freebore cause low velocities, and who feels that way?

I have always thought that more freebore was conducive to increased velocity but poorer accuracy. Weatherby has for decades used longer freebore to safely increase velocity potential of their rifles.
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I was waiting for someone to ask that, it took a little longer than I would have predicted.

Weatherby used the long free-bore to up his powder charges, which he could do since it lowered the initial pressure. It doesn't work when the cartridge case is already filled to powder crushing capacity.

Who feels that way? I suppose everyone who ever ran out of room in a four five eight case just about the time it was getting interesting, everyone who had compressed charges push the bullet back out of the cartridge, and most of those who have converted to the Lott.
 
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