9mm Brass Hourglass After Station 1

#1 · March 13, 2014, 1:40 am

Equipment: SDB and SD Conv 9mm 20241

Brass: Starline - New - 9mm - Empty - Unprimed
Also happening with Fed Premium

Problem:

When cycled through Station 1 the Brass now has an hourglass shape.

Dimensions out of bag
Base dim = .383
Mid dim = .379
Case Trim End dim = .374

Dimensions after Die #1
Base dim = .383
Mid dim = .3715
Case Trim End dim = .3705

So as you can tell, the middle is tightening a bit as well as the end.

You can visually see the hourglass and really feel it.

I am guessing the die has issues. It is the only thing I can think it to be?

Any suggestions? Thanks!

#2 · March 13, 2014, 1:50 am

My profile picture shows the hourglass on the cartridge on the left and the virgin case on the right. You can see it has a slight waist and does not have a linear taper.

#3 · March 13, 2014, 5:55 pm

Actually, your die is performing exactly as designed. 9 x 19 mm is a tapered case, not a straightwall. The size die sizes the upper portion of the case straight, then tapers outward below that. When a bullet is seated, the bullet expands the upper portion of the case, but a shelf is left under the bullet so it won't push back into the case upon feeding into a chamber.

#4 · March 28, 2014, 1:30 pm

Thanks for clearing this up. I was curiuos about this as well, but it did not impede the performance of any of my pistols. If a'int broke don't fix it