9mm reloading tribulations.

[Fred762]

Been a reloader for a number of years: started w a RCBS Rockchucker press and graduated some yrs ago to a Dillon 550. Mostly reload .38,.357mag and .45ACP but have done some 7.62x51 and lately some 9mm, and have run into some problems: Those little 9mm "tapered cases" are dang difficult to get right seems to me. I have ended up w about 1 case in 5 or 6 not sizing correctly, so that there is a slight bulge at the base (right above the extractor groove). I have tried to set the sizing die several times but it seems to happen no matter what.

I have measured the base of 6 different brands of "factory rounds" and THEY average out to 9.82mm diameter.. I have been measuring each darn resized case and tossing those which bulge or are more than 2/1000ths over-sized. This is waaaay too slow. Anybody got any ideas? There seems to be no particular BRAND of cases which is not sizing correctly..I did look at that.

Oh I 4got to add..I'm using Dillon 9mm carbide die sets .

[David Lewis]

Google is your friend: search for "9mm bulged cases"...& peruse some of the 13,000+ responses...seems to be a common issue.

[Fred762]

Nothing else seems to help except measuring the fired cases at the base, right above the extractor groove b4 resizing...
I reject any case mic-ing over 9.87mm or 9.88mm and toss it into a bin to be sent to comm'l reloaders [who use full length/roll or draw resizing].
I have had decent success resizing 99% of cases measuring 9.88mm or less..they easily size down to 9.82mm which is the avreage for 6 brands of factoy new cases i have on hand.
I have also found some foreign primer pockets are very 'tight' and need to be swaged out or bevelled out w a deburring tool b4 repriming. Another slow process!!
I guess some of my 'range pick-up' 9mm cases were fired in guns w BIG chambers..like carbines or FA weapons. WTH it takes a bit more time but I'm now getting nice looking, nice feeding, easy priming 9mm ball reloads for practice. Sheesh

[Fred762]

May have found the solution. Evolution Gun Works sells an 'undersized die' for resizing 9mm cases. I have ordered one and will let you know how it works. Be interesting to see if it works on those oversized "9mm cases" wh seem to be up to 10.003mm in diameter after firing!!

[Fred762]

Received the U-die the other day and immediately set her up in a spare Dillon die holder. I ran thru a bunch of 'oversized' 9mm fired cases, and voila' most of them came out ok, sizing down to 9.83mm at the groove..the average I use from 6 different brands of "new" 9mm factory loaded cases. There were still a few..about 5% which just will not resize to acceptable diameters and there seems to be no common thread w the: different brands and different once-fired diameters, etc. I dunno why. I think there's demons in some of them or something! I guess I'll save those up and send them off to a comm'l reloader after I get 1000 of them...which will take awhile!

The U-die has one problem..the die body is short and therefore I cannot use the die's lock ring on my Dillon die holder plate..so I gotta keep an eye on things to make sure the die doesn't back out, etc. Whatever. While I was at it I went ahead and gently 'swaged out' the primer pockets of every 9mm case I did on my Dillon swager rig, to make sure the new primer would fit easily. Worked fine and didn't slow me down too much, since I was using only that 1 die at this time anyways.