fire forming method for new cases

[nheninge]

I have been contemplating a new way to fire form brass. Call me crazy, but I don't like the idea of cream of wheat and toilet paper in a custom barrel!

I thought about designing a nicely machined firing chamber in a short barrel (same caliber) using the same reamer that ground my chamber. Then using light loads and a small hammer driven firing pin to launch an appropriately sized rubber/plastic projectile (SAFELY!) Ta Daa! Case fire formed!

However, before blowing myself up, breaking the law, and dialing 91 and putting my finger on the one, I decided to research. I came up with this. Almost exactly what I was thinking of (see pics).

Does anyone have any experience with this type of fire forming method?

I understand ballistics, and realize that even one trip to the hospital/jail is way more expensive than a new barrel.

Here are my thoughts:
- if a device like this can be used safely/legally, it would help extend barrel life
- since the chambers are theoretically exactly the same it should fire form the cases nicely
- I know light loads can be a problem d/t inappropriate interaction of the case wall and the chamber wall (more backward thrust and flattened primers, case head separation etc.
- some type of safe projectile has to be used since this pressure is what expands the case appropriately.

Safety is #1
Barrel life is at a premium, now more than ever
I don't like "glued-together-contraptions", but a well though out tool is what I want

This is clearly not a new idea, so any help appreciated!
Don't crucify me, it is just an idea!

 

[KRP]

Hornady makes hydraulic form dies, since safety and nobody calling the cops seem to be high on your list.

TECH TIP: Form Improved Cases with Hydraulic Forming Die « AccurateShooter.com Bulletin

 

[EddieHarren]

In my old edition of "Handloaders Guide to Cartridge Conversions" the author frequently refers to fireforming in a trim die. He does not furnish any illustrations but I would assume that his set up looked a lot like yours.

 

[nheninge]

Some countries (i.e.Canada) prohibit short barrels and can land you in trouble with the law on weapons charges. 1st Ive heard about the hydraulic dies. Thanks. Any personal experience?

 

[Boss Hoss]

Been using Bullseye for many years without the cream of wheat. Trick Speedy taught me---he forms all of his brass that way ----his own and for customers. He did so much of it he had a special rail gun that had several tubes for the most common rounds they did. Most of my rifles do not have a seperate tube for fireforming and when you do a couple of hundred it is no big deal.

 

[mo]

Boss Hoss just using Bullseye will do the same thing? How many grains would you start out with if you were trying to form a 280 to a 280 AI? I've never tried without the cream of wheat.

 

[Boss Hoss]

From the 22 Russian (6ppc) to the 338 Lapua AI I fill about 2/3 full topped with a little bit of cotton ball.

 

[mo]

Thanks for the info Boss Hoss

 

[dirtball]

From the 22 Russian (6ppc) to the 338 Lapua AI I fill about 2/3 full topped with a little bit of cotton ball.

Boss
One question, Large Pistol Primer, or Large Rifle, or does it matter?

Thanks
Dave

 

[Boss Hoss]

I always use LR ---- what ever I have that are old or that I bought cheap. Currently using the 25 year old CCI BR's for this.

 

[Varmint Hunter]

Why not just have a junk rifle chambered with the same reamer and fireform normally? Form enough brass for the life of your new custom barrel and then do whatever you want with the junk gun. You could rebarrel it with a factory take-off for almost nothing. Take-offs are available all over the web.

 

[mo]

Boss just tried your method. I got back a 284 win match from Nate 308. I was using 6.5x284 Lupa brass it worked great!!!!! I didn't even have to size it up, just primied put powder in then a little cotton, and it blew neck to the my chamber. Beats the heck out of lubing, and sizing up. Thanks again Boss for sharing your knowledge.....

 

[nheninge]

I like your idea vamint hunter. Was actually looking to do just that today. Safer too

Thanks

 

[Boss Hoss]

I like your idea vamint hunter. Was actually looking to do just that today. Safer too

Thanks

Speedy Gonzalez showed me how to do this---I have done thousands and he has done hundreds of thousands. Never a problem---just to a few at a time because the tube will get warm fast--let it cool.