300 Win Mag brass from 338 Win Mag brass?

[jkpq45]

Sorry--didn't know which forum to put this one in.

I have brass in 338 Win Mag. I have a firearm in 300 Win Mag. To transform the 338s into 300s, do I anneal, neck down and fireform? Should I neck down in steps? Should the brass be trimmed prior to fireforming?

Also--I have Hodgdon Clays available. Is 5 grains with a bit of toilet paper enough for fireforming, or should I FILL with cream of wheat, pack down and seal with wax? More/less powder?

Thanks,
jkpq45

[swheeler]

Sorry--didn't know which forum to put this one in.

I have brass in 338 Win Mag. I have a firearm in 300 Win Mag. To transform the 338s into 300s, do I anneal, neck down and fireform? Should I neck down in steps? Should the brass be trimmed prior to fireforming?

Also--I have Hodgdon Clays available. Is 5 grains with a bit of toilet paper enough for fireforming, or should I FILL with cream of wheat, pack down and seal with wax? More/less powder?

Thanks,
jkpq45

338 WM brass is too short to make 300 WM brass from, you'll end up with a very short neck, about 1/2 a caliber long. I've made 7mm RM brass out of 338 and it works fine, neck turning was not needed for my rifles chamber. Trade it for 300WM brass.