9mm chamber reamer dimensions question and looking for a test barrel.

I am ready to order a reamer for my continuing 9mm improvement improvement quest. My goal is shooting lead cast bullets as well as possible. I'm sizing the bullets to .356" now and think that in general this will be a good fit for most barrels. It is a good fit for my current guns.

My main question here is what diameter to make the cylinder section of the throat or freebore -- .358" seems right to me so the gun works when a little dirty. Any advice will be appreciated.

My current drawing calls for a .358" diameter by .040 long cylinder, then a 1 degree 30 minute throat. That calculates about right for .050 shoulder of the bullet past the case mouth. This cartridge dimension works well in the magazines and guns. Again, your informed comments on this are sought.

I am also considering making a 9mm test gun on an XP-100 Remington action that I have. I may bolt it up to a rail gun chassis or not. But a chunk of 9mm barrel would certainly prompt me to proceed with that project once I have the reamer. Does anyone have a short piece of 9mm barrel appropriately sized to fit up to the bolt action pistol action? About 1.150 minimum diameter.

Thanks!

Henry, I just did some work using a 9mm 10" twist barrel blank from Green Mountain.  It looked nice internally and shot well in my project.  If I remember it was only about $40 or so for about 18".  They might have other twist rates.

Thanks for that information.
I'm used to $300 plus rifle barrel blanks and was trapped in that thinking.
I'll look into those barrels.

Anyone have comments on my reamer dimensions?

I would stick closer to a standard minimum dimension finish reamer with that leade angle. In otherwords don't reinvent the wheel.
Jon