Home Forums Hunting & Shooting Custom Rifles & Wildcats .450 Marlin vs. .458x2" in a bolt action

I'm toying with the idea of building a .450 Marlin or a .458x2" on a short magnum Remington 700 I have laying around.

.450 Marlin

pros: - Cheaper dies (RCBS $56)
- probably cheaper and easier to find reamer and gauges
- brass available w/o modification

cons: - brass although available are not very common and are expensive
- availability of brass in the future

.458x2"

pros: - brass can be made from any magnum case
- cheap brass
- cool factor of a wildcat

cons: - expensive dies (RCBS $170)
- reamer and gauges probably not as easy to find
- brass needs to be modified

With both having the same ballistic I'm leaning towards the .450 Marlin despite the brass factor. Am I missing anything? Which one would you choose?

I would go the 458 x 2 American route, as brass is cheap and available which will offset the die price . Ammunition can be made from most .375 H&H Magnum cases including the .458 Winchester Magnum. Dies are available from RCBS and chamber reamers from H&M Tool Company. Look at using a 350gr Spire Point bullet like a Barnes TSX.

I like the 450 Marlin better.

The cartridge is 1/10 of an inch longer, and the brass is ready made. If you look into the 458 x 2 you will find out that you need to neck ream the brass to get it thin enough to use. Major pain. Use the powder and magazine length of 2.8 inches.

There was a good article in an old Gun World gunsmithing book about making and shooting the 458 x 2. I migh still have it somewhere. Tommy Bish if I remember correctly.

I too am considering building the 458x2. I setup a poll on CGN for the guys who shoot it, and all but one said no neck reaming required... That was my biggest worry. As for dies, I don't see why you couldn't use 450 marlin dies to load the 458x2. Everyone who chambers will have the gauges, as they are about as common as they come (standard belted mag). Reamers can be had for either cartridge without issue. While you can buy 450 brass now, the writing is on the wall and once it's gone there is no parent case to form more from (that I am aware of).

My vote is for the 458x2

I have a 458 American in a Remington 660. The gun is set up with peep sights and used for black bear and hogs.
I use Federal 300 Win Mag brass cut & trimmed back. I do not have to ream the necks with this brass. I use RCBS 458 American dies for loading. My favorite bullet is Speer's 350 grain bullet.

I have used the 458x2 for years. Ive had a couple built on 98 Mausers. Ive never had to neck ream. My dies are CH 4D. Dont over look them for your die options. Well made dies, small company and lots of options. The Marlin is a factory round with factory brass but for me its no big deal with how easy it is to make the 2". Good luck with your project.

I'm swaying back towards the .458x2"!

Yes, Steve; You are missing something! The very reason the .450 Marlin was invented to begin with. The problem with the .458x2 is that cartridge will potentially chamber in a .264 Win Mag, 7mm Rem Mag, .300... etc. And as the belted magnum cartridge headspaces on the belt, they, at least potentially will fire... With disasterous results, predictably... The .450 Marlin, due to its extra wide belt, will not!

The potential problem is: Even if you keep the rifle 'til your death, eventually it will fall into someone else's hands. They MAY chamber your leftover ammo in whatever rifle the headstamp bears... NOT a good scenario... That person may be your son, or grandson...

I have both, and I have every intention of returning my .458x2 to it's original chambering; .350 Rem Mag.

My $.02, FWIW...

I didn't miss that. I am aware of the wider belt on the .450 Marlin and the reason for it. I still think it is highly unprobable that someone would mistake a .458x2" cartridge for a .264 Win Mag and try to chamber it in his rifle. One could always only use .458 Win Mag brass if makes him sleep better at night.

Hey double gun, your poll brough back the idea of the .458x2". Good point on the gauges kind of forgot that it headspace on the belt so any belted mag gauge would work.

Re-reading JB's article on his 9.3BS and how he switches the barrel back and forth with the original 7mm SAUM barrel also got me thinking that I should do the same with my 7mm SAUM.

Here's a pic of my Rem. 660 in 458 American. It is a very handy rifle with the peep sights. However I have been thinking of have a forward scope mount made so I could use a scout scope and still get to keep the peep sight set-up.
I think only a Darwin award candidate would put a 458 diameter round in a 6.5 hole. Also if the case designation bothers you that much, Qual-Cart makes 458 American labeled brass.
Good luck with your project.

Do you have a hidden second recoil lug? No stock splits? Barrel make and contour?

Good bedding will cure many of those woes.

bigJ....Not sure on contour, but the barrel is a Douglas and it does have a second hidden recoil lug. The action through the second lug are bedded, past that it is free floated. There have been no stock issues. It also has a metal trigger guard. I can take a picture of the second recoil lug if that will help.

With a bullet seated, I don't think a 458x2 will fit into a 264 or 7mm Mag. Might go into a 300 Weatherby or STW.
I had a 450 marlin reamer modified to use the standard magnum headspacing (.220")and it worked out fine. If a person wanted the Marlin headspacing, it could be done with a boring bar. GD

I would love that, if you have one on hand - I dont expect you to pull it apart for a pics though.

Greydog, could you please explain what they "altered" on the 450marlin reamer. Couldnt a guy use an unaltered 450 marlin reamer, but standard magnum gauges? I thought the only real difference was the belt length... (but I dont have the cartridge drawings in front of me so I could be wrong)

Double lugged barrel.

Thank you very much for the pic. That is nice and neat... If I build I will need to copy that.

Why the double recoil lug? A lot of cartridge kick more than the .458x2" and only have one recoil lug.