Sizing 9mm to...?

[JBD]

This is what I suggest. Powder coat then size in 357 sizer. Then powder coat and bake at 455 for one hour then quench in ice water. This heat treating will harden your bullets if made from wheel weights. 9mm is fairly high pressure cartridge. I am using a couple different mp molds.

You will likely have to shorten oal to function with any mp mold. If so consider loading below minimum suggested and work up watch for pressure signs. I love mp molds but so far non of them work in all my handguns without reducing oal. The lee tl356-124-2r works in everything.

 

[Helka]

This is what I suggest. Powder coat then size in 357 sizer. Then powder coat and bake at 455 for one hour then quench in ice water. This heat treating will harden your bullets if made from wheel weights. 9mm is fairly high pressure cartridge. I am using a couple different mp molds.

You will likely have to shorten oal to function with any mp mold. If so consider loading below minimum suggested and work up watch for pressure signs. I love mp molds but so far non of them work in all my handguns without reducing oal. The lee tl356-124-2r works in everything.

Thanks. I have the Lee 6 cavity on route as well. The MP mold doesn’t have any lube groves so it’s made specifically for powder coating. So I’m hoping they took in consideration the ogive for seating and made the bullet a hair smaller.

 

[Auggie Doggie]

400 degrees for 15 minutes is plenty, just do a hammer test after. No real need for additional hardening of WW alloy if you have powder coated them. I have shot THOUSANDS of 9mm and had absolutely no issues. Cooking them for one hour is just wasting time and electricity.

Auggie D.

 

[Helka]

400 degrees for 15 minutes is plenty, just do a hammer test after. No real need for additional hardening of WW alloy if you have powder coated them. I have shot THOUSANDS of 9mm and had absolutely no issues. Cooking them for one hour is just wasting time and electricity.

Auggie D.

Thanks for the info. I value everyone’s input as this is a new venture for me

 

[JBD]

400 degrees for 15 minutes is plenty, just do a hammer test after. No real need for additional hardening of WW alloy if you have powder coated them. I have shot THOUSANDS of 9mm and had absolutely no issues. Cooking them for one hour is just wasting time and electricity.

Auggie D.

there is no official formula I am experimenting as well. I was water dropping in a bucket that is plenty hard for 9mm and 44 magnum but when we powder coat and let the bullets cool then I was losing my hardness. The powder coat protects from leading regardless of the hardness of the projectile. Except dead soft lead yep tried that to. However matching bhn to chamber pressure I found better accuracy. That is why I am doing it.

 

[mulenv]

True Caliber is Lans to Lans.
That's Rifling to Rifling Cut. That's where your pressure is going to base generate at.
The guy saying Bore Slug could have a point. U can cast your bore to start with and then measure the shrunk back outside grooves. just remember unless using ID micrometer.
I don't know about CZ pistols but their rifles have a tight bore; which is separate subject but will affect Flow of said projectile depending on it's composition and your charge.

 

[Shua]

I have decent luck casting with an MP mold, then PCing and sizing to .357. A few get scrubbed a bit on the sizing pass occasionally. Back in the pot they go. Have Lyman and Lee molds, but they drop a touch smaller, ending up at .356 even with PC and the .357 sizer. Have had leading because of it. The MP is one of the nicest moulds I own to use, right up there with a vintage H+G for ease of use and quality castings. Not many rejects if I do my end. Would like another .... I don't water drop any, I'd like them a little softer for expansion. I use almost anything plumbous for plinking, but generally it's at least 25% clip on WW, up to 100% clip on WW.