07 December 2005, 21:44
ark_firemanTrying to form 375 jdj brass, need alittle advice please
Today I made my first attempt to form 375 jdj brass from 444 marlin brass. I have made 7x30s from 30-30s before without problems. I tried my usual steps, lubed with one-shot and mica in the neck but when I ran it through the sizing die, it just didnt want to go... at all. I put pretty good force on my press trying to make it size but I felt like if I pushed any harder the case was going to stick. What am I not doing right? These are hornady dies with good, clean brass on a rock chucker press. Any advice would be appreciated. Thanks, John
07 December 2005, 22:18
kidcoltoutlawIm getting ready to do the same thing soon. I have read this try Imperial sizing die wax . Try this link to
http://specialtypistols.infopop.cc/groupee/forums07 December 2005, 23:07
jffrybrghtmake sure to chamfer and de-burr all the 444 case mouths first. If any of the 444 case mouths are out of round, you may get a collapse in the shoulder area as well.
08 December 2005, 02:32
HLNot to ask a stupid question, but are you sure the dies are for the 375 JDJ?

I've always used the RCBS lube to form this brass and have never had a problem. Also, like stated above, I make sure and chamfer prior to sizing.
08 December 2005, 03:04
kidcoltoutlawI have been told to run it through a 44 or a 444 die to make sure the neck is nice and true also,
Thanks,Keith
08 December 2005, 05:15
ark_firemanYes, the dies are 375jdj. I dont know what I was thinking when I said I was using one shot lube. What I was using is hornady unique. I've been using it for about 10 years and have never stuck a case. But it doesnt seem to be doing the trick on my 444 brass. Anyway, I dug around and found my old rcbs pad and lube just to give a shot and the case sized alot easier. I chamfered and deburred a few and ran them through and a couple of them started to split alittle at the mouth. I'll try running them through a 44 die to see if that helps. Thanks for all your advice fellas. I'll let you know how it all turns out. Thanks again, John
08 December 2005, 07:02
jshYou might want to anneal the cases first if the splitting persist.
Jeff
08 December 2005, 16:17
McCluraI'm pretty sure One Shot is not for sizing cases like that. I have had trouble using one shot just sizing necks. Go with RCBS liquid lub and a pad. I've never had a problem with my 375jdj or 309jdj
I roll the brass on a pad with RCBS lube and put some inside the neck area with a q-tip. It does take some presure but they always work.
If you need some formed brass let me know to get started. I have some extra that has been fired a few times. Just run them through your dies and load so they will form to YOUR chamber.
Mike
10 December 2005, 18:21
Bobby TomekOn these cases, I found that you must first true them up in a .444 die (or anything similar) so that the case mouths have any dents and rough spots ironed out. After that, the problems magically go away.
Also, I've used Hornady One-Shot for necking down the .444, and it works just fine as long as you have a smooth, tapered expander. Most expanders do require a little polishing to get them to perform best.