Resizing .30-40 brass to .303 British?

[Jenrick]

Doing some research on loading .303 British, and I saw an article advising using .30-40 brass full length sized and trimmed to make .303 British brass. The article claimed much long case life, stronger case necks, and in general superior performance. My .303 operation is a quantity loading process (not like I need 1K .303 British for a rifle class or anything) so if there is an advantage to producing it out of .30-40 I don't mind the extra steps. Does anyone have any knowledge of this?

Thanks in advance,

-Jenrick

 

[Ifishsum]

I had picked up some .303 brass at the range a few months ago with the idea of sizing them into .30-40. I don't have a lot, maybe 20 but I'd trade you if it's worth the postage. R-P cases, once fired by all appearances.

I know that if I size these to .30-40 they will be just a little short, but usable. I see no reason .30-40 wouldn't size to .303 as they are very similar, but I have no experience yet either way. Either cartridge is getting fairly uncommon it seems.

 

[FROGO207]

FWIW I get good case life out of the available Boxer primed .303 brass--RP, WIN, PPU, etc. Also WIN sells packages of 50 new brass for a reasonable cost IMHO. Not much different in cost than .308 as I found at Natchez. The 30-40 Craig brass will cost MUCH more and you will need to do a bit of work up front the first time to use it besides. The key is to fire-form any of the brass to your chamber and subsequently neck size or bump them back just enough to fit the chamber again. Most .303 BRIT rifles have huge amounts of head-space so reloads do not last but a couple firings if full length resized. There have been a couple threads on this topic here in the reloading section but I am not good at linking posts. I would do a search for "reloading 303 BRIT". John Ross is the expert on this and any of his articles/posts are worth reading IMHO.

 

[Curator]

"Some" .30-40 Krag brass has a slightly larger case head than commercial .303 British brass and will center better in Lee Enfields with large chambers. While the Krag case is longer, the shoulder length is slightly shorter. I have made .303 Br cases from Krag brass when I had lots of them and the .303 was hard to find. Also if shooting cast bullets in the .303 it helps to have case mouths that are not short in the chamber. That's where the Krag brass really helps. Most Lee Enfields have chambers cut generously both in length and diameter. Fire-forming the Krag case in their chamber with a thin "O" ring under the rim to keep the case head solidly against the bolt face, will show the exact trim-to length for best performance with cast bullets. It will be several thousandths longer than the specified 2.22 inches, perhaps as long as 2.30". Once made these cases should be resized using the Lee "Colet die" to extend their life. I have some made for a generously chambered No.5MkI carbine that I have reloaded more than 30 times and they are still good as new.