fireform 300h&h to 375H&H?

[rp85]

good morning;

discovered cost of 375wby brass, but have a fair amount of 300H&H brass. Is this a reasonable game plan or even possible.

fireform 300H&H cases to 375H&H, load these newly formed 375H&H cases and fire them in the 375 wby for final fireforming?

goal is to have several hundred 37 wby cases.

thanks for any input.

rp

[Wayne Smith]

If you can find a die with an elliptical expander button you may be able to expand them. Polish the expander well and lube. Otherwise, fireforming them is your best option. You will need something to block the top of the cartridge case, wax or a paper ball. If you have BP it will work very well for this, other wise a very fast pistol powder is what I have used - although not in a case this big.

[15meter]

And why not fire form in one shot?

I've taken 7mm Remington Magnums to 458 Winchester in one bang. Think I annealed those before fire forming. One of the few that I annealed before forming. I think I even posted a write up about it awhile back.

[15meter]

Look here:

https://castboolits.gunloads.com/showthread.php?431146-Fire-forming-458-Win-Mag

My ramblings on fire forming, worth every penny paid for it.

I typically use old odd stuff for fire forming, recycled primers from reloaded ammo that comes my way--"here you shoot rifle, these were my dad's, I won't shoot them!"

I picked up enough fire forming powder this spring to last me the rest of my life, 60's(or earlier) pistol powders that still go Kaboom! Nicely.