309 JDJ BRASS

Do any of you guys know if you can form 309 brass from 444 marlin brass. I tried a couple but the brass just collapsed.

The 444 Marlin is the parent case for the 309 JDJ. Take a close look a the case mouths (444 Marlin) they need to be perfectly round. If not they almost aways colapse when you run them into the 308 Winchester die. I run mine though my 44 mag expander die to true up the case mouths. Try not to bell them. A slight bell doesn't seem to hurt but I try to avoid it.

do I need to run them through a 308 die before I use the 309 die?

yes, and then fireform. The shoulder angle on the jdj die is too sharp, that is why yours are collapsing.

THANKS, THAT MAKES SENSE

When you run them through the 308 sizer die, adjust it down just a bit at a time.....keep adjusting down until your action will just close on a formed case.......if you push the shoulder too far back, the brass will stretch in the web the first time it is fired.