Does this make any sense ??

So I set up a 458 winmag barrel, but for now for the most part I want to load a 300 gr bullet at about
2000-2200 fps. The heavy stuff will come later.

I can load a slow bulky powder like H4895, and get an 80% burn, almost complete fill and a huge fireball.

I could also load a faster powder like imr4198 or RL7 and get a faster almost complete burn
but at about an 82% case fill which I am not thrilled about.

With that I am somewhat concerned about hangfires and or secondary ignition etc.

I could also load a fast powder and use a filler which I am not too wild about.

So I call Hodgdon, they would not even discuss it.
Great.

I called Barnes and they said just load it up with H4895. 80% burn.
At least they talked to me.

Another option I ran into is supposedly you can shoot a 458x2 american wildcat through a 458 winmag chamber.
458x2 American is a winmag case shortened from 2.5" to 2".

So lop off 1/2" from the winmag case, trim it and load it as a 458x2 American.
Basically the same as a 450 marlin but with the normal WM band, and about the
same ballistics as a 450 marlin or a hot 45/70 load.

If I load the 458x2 up with a 300 gr bullet and RL7 or 4198 a 104% case fill gets me to the
exact speed I am looking for at about 40-45k with about 4-5# less recoil due to less powder.

The 458x2 would actually run through a Short action which would be nice for a light rifle
although from scratch a 450 marlin would make more sense.

Sort of the same thing I do with my 44 magnum handgun, which is load light loads in 44 special which is safer.

You aren't going to get hang fires with 4895 or 4198 neither is a "slow" powder which is what causes hang fires. I also don't think you are going to get a huge fireball with 4895 or only 80% burn.

I would go with light loads of 4198 or 3031 as I mentioned before (I load as light as 28 grains of H4198 behind a 400 grain cast bullet in the 45-70 with no problems).

The hang fire/secondary ignition thing comes when using slow powders in the big cases (like 4831, H1000, 870, etc.) not with the relatively fast/medium powders used in the 458.

No need to go with the short case for the velocity you want - like we said before, use some 45-70 data and you will be fine.

The 458x2" requires that you either A) inside neck ream after you trim or B) fireform 350 rem mag and trim cases - the freebore firing it in a458 Win chamber will certainly not help accuracy.

Probably going to just stick with the 458 winmag loaded with H4895 but just out of curiosity I dont really
understand why you would need to neck ream a cut down straight wall case.

Because when you cut the case down the area of the case wall that is now the "mouth" is much thicker (i.e. the case mouth is now less than .458 in diameter). If you try to seat a .458 slug in it without inside reaming it, you will get a big bulge in the outside of the case and you can bet your bottom dollar that your bullet will be off center to the bore.

If you fire form the shorter 350 Rem Mag, you don't need to trim nearly as much length down and the case neck/mouth is thinner anyway because it stretches from 358 to 458.

4198 is certainly the easiest way to get where you want to go. You could also try SR4759 for loads in the 1,700 fps range.

Yeah after I posted I thought about it a bit and thought that was the case.

Well now I know about the 458x2.

I guess it would be an option if I ever wanted to run this barrel on a short action.

Thanks