Looking through CARTRIDGES OF THE WORLD I got to wondering if it would be possible to use the 458x2" American in the 458WM? The 458x2 is what the 450 Marlin should have been and to all intents and purposes is, except you can't use it in the 458 WM. A little help from the more learned would be much appreciated.

I don't know about it being safe to fire a .458x2" in a regular .458 WinMag chamber but as it's about 1/2" shorter I wouldn't care to try it. At best you run the risk of shaving a lot of bullet if not centered properly.

With respect to the .450 Marlin they made the belt the width they did to keep people from trying to chamber it in something like a 7mmRemMag or .300 Win Mag....you could have closed the bolt OK but it would have been very noisy when you pulled the trigger plus you would have had to have all that annoying pieces of steel and wood removed from your body.....Marlin did the right thing.

I haven't tried it, but if one can shoot a .22 short in a long rifle chamber, a .38 Spl. in a .357 Mag. chamber, or a .44 Russian, or .44 Spl. in the .44 mag. chamber, I don't really see why it couldn't be done. About the only real problem that might occur is there could be some serious erosion of the chamber where the shorter rounds ends. Accuracy might suck as well, but I don't really see a kaboom from trying it. This also doesn't mean I think you should do it. You never really have a clue as to what might happen.
The fact that it is possible is a theory, by me, not supported by actual test firing by me
Paul B..

I don't think it would be wise. I read an article and saw a page on the web where a man fired, if I am right a 270 cal bullet through a 7mm bore. They were magnums and I don't recall which specific chamberings. Any how the bullet caught the shoulder and cocked, thereby peening itself in the throat area. The gun came apart and the barrel went down range like a little rocket for about thirty feet. All of the assumptions were backed up by photos and "expert" analysis. I would guess the major reason it is acceptable in handgunning is that there is not really a sharp cut throat area but a more gradual forcing cone. There will always be exceptions to the rule but I wouldn't try it here. Who knows, I guess it is OK to fire 458 win mag in a 458 Lott in a pinch. I don't have any af the above so I'm just guessing, as Paul says, it is only a theory.

Unlike the 22 rf, and 38 sp mag chamber, the 458 case is not a cylindrical case, it is tapered. As a cylindrical case, it would be a .475".

A better approach would be to down load the 458 win mag to 450 marlin levels. I downloaded my 458 lott to win mag levels, no reason you can't do the same thing. I used Reloader 7 and both speer and hornady 350 gr bullets. The speer produced its accuracy at lower velocities and charges then the hornady rn. Me thinks you ought to be able to load a 350 gr @ 2200 fps in the win mag.

If you want milder then that, you ought to be able to push a 400 gr cast 1300 fps with 2400.

THE STATEMENTS YA'LL HAVE MADE WERE WHAT I HAD EXPECTED TO HEAR. I THOUGHT IT MIGHT BE POSSIBLE, BUT NOT SOMETHING ANYONE WOULD ADVOCATE DOING. MY INTEREST IN FIREARMS LIES IN THE BIG BORES HOWEVER BEING REPEATEDLY PUMMELED AT THE BENCH ISN'T MY IDEA OF A ROLLICKING GOOD TIME. I READ AN ARTICLE BY KEN WATERS TALIKING ABOUT THE DIFFICULTIES OF DOWNLOADING THE 458 WM. I GUESS I NEED TO STUDY SOME MORE. THANKS ALL.

FWIW: After reading this topic I went out today and fired 10 rd. of 458x2 that were loaded for my T/C handgun in my Ruger 458. At 50 yd. they grouped about 1.5" and didn't appear to do any harm. I then resized the cases also with no damage apparent.Mark

WELL THANK YOU VERY MUCH MARK358 THAT WAS VERY BIG OF YOU TO TRY THAT. I CAN IMAGINE THE FEELING YOU GOT---HMMM? WILL THAT WORK? I'VE GOT INSURANCE, SO LETS TRY IT! I WAS LED TO PONDER THIS QUESTION DUE TO THE 458 WIN MAG IN THE 458 LOTT SCENARIO. AT LEAST I KNOW THAT IT CAN BE DONE KNOW.