I have a .458 Pac Nor barrel 20" long with a 20" twist rate. It's chambered in 450 Marlin on a Ruger short action, but that experiment did not work out too well because it doesn't feed well enough to suit me.

So, I have another Ruger action - a long magnum action - which will feed the 458 WM just fine, with no modifications. I probably should have used it in the first place. My gunsmith says that setting barrel back one turn, and rechambering to 458 WM should clean up the 450 chamber.

So, my question for you knowledgable guys is this 20" twist rate going to be proper given that my bullet of choice is the Swift 400 gr, or perhaps the Barnes 350 gr, or maybe some of the other 350 - 405 gr bullets. I will probably want to use some cast bullets too, in that weight range.

Thanks,
KB

Do it.
Use the GSC HV bullets technical data page:

For a .458/400-gr HV a 1:23" twist gives a gyroscopic stability factor of 1.5.
A 1:27" twist gives the minimum for longrange target use, 1.1 stability factor.

350 to 405-grain lead-cored bullets should do fine in a 1:20" twist. So would a 350 to 400-grain monometal copper bullet that is not undersized.

Faster twist would be better for a hunting rifle for use under 500 yards, especially with the long and heavy monometal copper bullets, but if you want to use cast lead bullets, the slower twist will be an Okay trade-off.

458 AR!

quote:

Originally posted by boom stick:
458 AR!

Boom,
My question was concerning twist rates, as I have my mind on the 458WM, to keep things simple.

Since you brought it up, exactly what is the 458 AR, and why would I want one? Seems to me the 458WM would be over kill for most anything. I want a big bore for those times when I'm walking around, berry picking, or fishing where the bears might be, or perhaps for another moose hunt, or to mess around with cast bullets. If I wanted, or thought I needed more power, I would get a CZ in 458 Lott. But I don't think I need more power than the 400gr swift will produce at 2300 - 2400 fps. If I do, well I suppose I'l just have to make do with what I've got.

Since it's not more power that I want, does this 458 AR feed better, shoot straighter, Feed & fit the unmodified action better? Is brass easier to find? Is it easier to reload? Can I find factory ammo? Do I need custom and expensive dies and special reamer? When I get ready to sell it some day, will it be easy to sell? How many of these 458 AR cartridges can I get in the magazine of my Ruger action - two or three?

I already tried something unusual - the 450 Marlin in the Ruger short action - and it just isn't ever going to be slick enough to give me the assurance I need with such a rifle. The way I see it, the 458 WM is as close to a sure thing as I can get. I have already tried feeding cartridges through it and it's slick, so I don't have to modify anything with the action. With the AR, maybe - maybe not. It may be too long - or maybe too fat, maybe if I remove just a little feed rail here or there, or maybe grind some feed ramp off will improve it. That's what I want to avoid. It's just no fun to ruin an action, plus spend a lot of money doing it, and the stuff I end up with has no resale value.

As you know, I have no problem with wildcats, as I have one and another on the way. But I see no reason for a wildcat for this purpose. If you know something I don't on this subject, please inform me.

KB

1:20 works fine for 400gr jacketed, and will work great with heavy lead bullets.

458 AR fits and feeds from an unmodifed ruger receiver very well, and the shoulder helps feedings, at least compared to the 458 winmag.

jeffe

I would like to buy three dummy 458 AR rounds, loaded with 400 gr bullets. State your price.

How about $20

Thanks KB

quote:

Originally posted by Kabluewy:
I would like to buy three dummy 458 AR rounds, loaded with 400 gr bullets. State your price.

How about $20

Thanks KB

..................Way to go KB ...,I,de like to try them is my 458 when you get them

shipping to AK?
Which bullet would you like, remmie 405s? Woodliegh 400gr?

I don't have any 400 gr barnes on hand

I'll be happpy to share
jeffe

Given the choice, I would prefer the Woodleighs.
Do you still have my address from the FN action deal? If not, I'll PM you.
Thanks.