Reloading 9mmx57 mauser. Does this look OK to you?

OneBarfly

OneBarfly

CGN Ultra frequent flyer
Rating - 100%
106   0   1
Location
My Livingroom Office: Ont - Marshes of the east
OK - I finally got to take my 9mmx57 Mauser out for a run. It's a pre-war Lightweight German Mauser bought from TradeEx. I tried both factory loaded ammo (vintage 286 grain WRA dated from the 1930's) and my own reloads. (Hornady 250 grain - sized down to .356). I used Redding dies. My reloads clocked around 1,900 to 2,000 FPS. The factory 286 grain were around 2100-2200 fps.

While the recoil was very heavy, the rounds seemed to group OK. I chalked this up to the light weight configuration.

After going thru the brass yesterday, I beginning to wonder if something different is going on?

In the picture below, you can see a little extra "ring" just beyond where the case neck is on both my fired reloads and factory spent casings. Also, the case mouth seems to have a greater crimp on it after firing? I think that this may be an optical illusion - I did slug the bore to confirm 9mm. Any ideas what going on here? Just my imagination?

9mm%20mauser%20scan.jpg
 
You can use 358 Win loads for the 9x57, and should be able to get 2250 fps with a 250gr bullet. I bet that RL15 would work nicely.

The ring seems to indicate a rough chambering job in the neck area, but the "crimp" should be cause for alarm. That could happen if the brass is too long for the chamber and is being pinched when the bolt is closed, which causes pressure to skyrocket. Check your brass length and if ok, have a gunsmith look at it - he might need to run a 9mm neck reamer into it to lengthen (and clean up) the neck.
 
I agree. Trim another .005 to .010 off your brass and try again. Also, a lot of these old rifles may not have the cartridge they were chambered for marked on them. A casting of your chamber will definately let you know what is going on.
 
You must log in or register to reply here.
Back
Top Bottom