resize .357 brass in a 9MM die?

[fjlee]

fjlee,

a little footnote to post #13 above: the 9mm sizing die i use is an old steel rcbs. the carbide sizing dies won't work. with that steel die i get an extra .002" reduction in diameter with that die, down to .373".

with .010" case neck dia., the i.d. is now .353" instead of .355". i run it in a .354" expander plug and get .003" neck tension instead of the normal .001".

murf

Murf.......Tnx for the 2 responses. It's nice to get some actual numbers/dimensions from you. I've put the numbers you supplied into my "reloading experiments" log.

Since I don't own any 9MM or any other resize dies that would lend themselves to the resize experiment I want to do......I think I'll do this:

I'm a retired machinist, and have lathes, etc here in my home workshop. I think I'll make my own resize dies, with dimensions to suit my experiment. I have an arbor press, so a "press brass in, press brass out" type resize die works well. Resize the case for a distance of abt. .280 inch, which is the approx. bullet seating depth. I've done this before.

Probably make 3-4 of 'em, in steps of .0005 inch ID. 5/10,000ths inch per increment TIGHTER than my current .357 resize die. I can make 3-4 of 'em just abt. as quick as making one.

Get some stock, drill undersize, bore VERY slightly undersize, then lap to final desired size with mirror polish.

This is a GOOD LOT of WW brass I'm working with. It's been reloaded by me several times. Never cracked or crumpled one of these cases yet......and haven't annealed any of 'em. I'm sure that the brass _IS_ work-hardening, especially at the case-mouth, but I've yet to discern it.

FjLee Denver CO

 

[murf]

one more note: when you reduce the diameter of the case the internal volume goes down, also. pressures will go up a bit with your old loads so, i would reduce and work up a new load.

when i tested the new sized cases with the original load, velocity increased (pressure went up) a bit (from 1520 to 1585 fps). be careful.

murf

 

[Jim Watson]

Suggest your DIY die be made and adjusted to just neck size, with the case below the seating depth just conventionally resized. Actually, RCBS has made .45 Colt dies like this to give good bullet pull on .452" bullets and not overwork case bodies in chambers cut for .454" bullets and black powder.

 

[kopcicle]

Just a thought . even if all six chambers vary a bit have you considered a full length anneal and neck size onto a reduced load for fire forming purposes and send the brass out to your favorite die maker ?
It's not unheard of to request weapon specific dies . How do you think my .475 wheel gun operates safely and accurately? Why am I able to get my .270 brass through the press 8 times or more ? Why does my 1911 platform provide uncanny accuracy along with rattling in the rails reliability ? All have had fire formed brass sent to a die maker to build ammunition for that specific chamber . I do believe a separate die for each chamber of a revolver is insane over kill but I know of at least one who does not .
YMMV...
~kop

 

[murf]

another fyi,

when i size the 357mag case in the 9mm die, it only sizes the first half inch of the case.

murf

 

[fjlee]

Yup........and yup.........

To quote what I wrote in message #26:

"Resize the case for a distance of abt. .280 inch, which is the approx. bullet seating depth."

FjLee Denver CO