Any reason I can't resize 375 RUM brass for domestic (range) use as 404 Jeffery?

Thanks,
Todd

Works like champ. If you use the Imperial sizing wax you can do it in one pass, easy to do, trim and you're good to go.

You might want to check the case heads.....I believe the RUM cases are slightly rebated and the jeffery cases are not.

The on hand Norma .404 head dia. is very close to .541". The Mast or Bell measures almost .001" greater. The .375 RUM cases are close to .546" in dia. The rim is rebated in the RUM by .010".

I don't quite remember the whole story but I know I wound up doing some serious chamber lapping in one of two rifles.

If your chamber and dies are capable as far as size you may just be fortunate as was Head trauma. It's got to be woth a try. roger

Gathering data. Good to know, worth a try. Barrel / chamber would be Lothar Walther.

Thank you gentlemen.

Todd

My .404 is essentially living on .375 RUM brass these days. I have converted over 200 rounds of the RUM brass to .404 without a single failure either in the conversion process, or in firing the brass several times after the re-forming.

The base dimensions of the brass is irrelevant in my measuremnts, as the .375 brass, and Kynoch Boxer and Berdan cases actually overlap in their diameters.

Simple resizing won't do the job, at least with my tooling.

To make .404 brass from .375 RUM, I do the following:

-remove the decapping stem from the .404 sizing die

-size the .375 case until the case will JUST allow the rifle bolt to be cammed closed over the case...a good bit of "feel" on the bolt handle is a good thing here.

-prime the partly-formed case, drop in 20 grains of 2400, and fill the case almost to the mouth with cornmeal.

-tuck a piece of paper towel, or toilet tissue, or a tuft of dacron into the mouth to hold everything in place.

-transport these strange-looking "loads" MOUTH UPRIGHT in a box or loading block to a place where noise isn't important, and....

-fire them VERTICALLY into the air....if they're not fired vertically, I've found that uneven case mouths can result. Vertical firing has given me brass that doesn't even need trimming to even-up the mouths.

I tried using .300 RUM brass, and the neckwall thickness ends up a bit thin for my taste. .338 RUM brass works, but the cases start out a bit too short, and they stay that way. .375 RUM is juuuuuuust right!

I use almost the exact method Bren does to make range brass for my 404j. The only diff. is I use 18gr of IMR4227 & plug the case mouth w/ a bit of melted candle wax. The brass peforms just like Norma factory but I still would use Norma for hunting.

quote:

Works like champ. If you use the Imperial sizing wax you can do it in one pass, easy to do, trim and you're good to go.

X2 - I have a set of CH4D dies which are not the prettiest I ever saw but, I can form them in one pass using Imperial Sizing Die Wax. I converted a PF Model 70 to .404 and the only problem I had was feeding. As far as loading firing and extracting, there were zero problems. The only departure I had to the quote was that they came out about 1 M/M short and trimming was not necessary. It will probably be necessary after several firings due to the very shallow shoulder angle.