The thought is low pressure, velocity and noise with a LARGE cast boolit. That could be made to function in a M-98 Mauser with little alteration. That's why the 06 sized case head idea. I'm thinking of not inside reaming to simplify makeing cases as long as it will feed reasonably well.



Looks like my pics aren't showing up anymore.???

I picked up a bag of 284 win brass today and cut a few off at the sholder. I then exanded with a 45-70 die and seated the variety of Lee 457 boolits.

left to right
45-70, 500-2.515", 450-2.515", 405-2.255", 340-2.247" and 284 win case.
The cases are cut to 1.8". Do you think that they would reliably headspace off of the case mouth? The long ones feed fine in most of my Mausers and the short ones only feed in some of them.

Apparently,the .45ACP headspaces ok in a bolt action gun.
I measured several .45 ACP cases and they had a wall thickness of .0095 in.

If the chamber was reamed correctly and you were careful with the trimming and chamfering,it could probably be made to headspace safely.

You would have to neck ream these cases and be careful
to not anneal the cases too soft.

If you are using a barrel with a .458 groove dia.,you would probably need a cast bullet measuring .4585-.459 in.
for accuracy.With a.010 wall thickness at the mouth,your case would mike .479,add .003 for clearance,the mouth of the chamber would be .482 in.Most chambers for wildcats on
the .284 Win.case have a base dia.of .500+or-.001.There would probably be enough case taper that it could be made to feed reliably in a bolt action.

If you opted for a thicker case mouth,it would provide more to headspace on but would probably decrease the reliability of the feeding.

I would probably go with the .450 Marlin but it's your $$,
if you try it,let us know how it works out.

WC

What kind of pressure do you plan on reaching? Why not just use 300WSM brass and that way you would have a shoulder for headspace?

Lar, that is a very cool looking toy you have made. But would it not be easier to just go 458x1 1/2 Barns, or the 458x2 American?
You would have a much easier time head spacing, and tons of Mag brass to trim down..
You would require a little more rail work than the 284 cases and mag bolt face.

Not trying to change your mind, just wondering...

Way to much fun...

The cartridge you have made is the .45 Professional that is chambered by LeMag in AR-15s. They had a write up on them in one of the Guns&Ammo annual editions, 2000 IIRC. He was using .451 caliber bullets and pushing them to some extreme velocities. With the longer but narrower case, I expect this round to perform alog the lines of our .458 SOCOM. THe higher pressure rating of your brass will afford some additional fps ... keep us posted