303 British to 444 Marlin

[RustyReel]

Just wondering. I see posts where guys are making .410 shotshells out of both 303 British and 444 Marlin. So, is it possible to make 444 Marlin from 303 British. Would be fired in a single shot so I don't think length would be an issue. 303 Simply fireformed in a 444 chamber?? Don't really need to do it right now but just wondering in case I need to some day. Thanks.

[Mk42gunner]

You could try trimming most of the excess length off before whatever expanding you do.

I never got rid of the wasp-waisted look when I tried making .410 shells from .303 brass, even after two or three firings. .444 Marlin is considerably higher pressure than a .410 though, so it might work.

I wouldn't get my hopes up about this conversion. It may take a few firings to fully fire form the brass, and with the cost of primers these days it just might be less expensive to buy some once fired brass to stick back in the locker.

Robert

[wilecoyote]

......thanks for the input, new-to-me, yet it was the first thing I verified about the possibility of obtaining .444 from other cases : I'd never thought about it, but I'd like to know more, especially about annealing, if any, if advised, for low-recoil plinking in my lever.
if nothing else, something new for me to try and a good reason to scrounge around some .303 case...

[screwcutter]

You will end up 20 thousandths or so short at the base, if they survive fire forming.

[wilecoyote]

You will end up 20 thousandths or so short at the base, if they survive fire forming.

...thank you: your if seems at least really interesting

[john.k]

Many years ago I had a 7x57 rimmed,for which cases were unavailable to me at that time......so I soldered a wrap of brass shim around the head of 303 cases to increase the diameter .......then a quick size in a 7x57 Mauser die ,and they worked perfectly......(Incidentally ,the brass shims were actually engineering workshop ID labels ,written on and wired onto jobs to identify them........unlike paper labels ,they were nearly indestructable)