HOW DO THEY????

[bowhunternut]

Hello there anyone know how they take brass lets say a 223 rem case and turn it in to a 7mm tcu case??

[Ridge Runner]

ok, if you take any brass and make it tight in the front of the chamber and the bolt holds the back of the case (minimal headspace) and fire it, it conforms to the exact shape of the chamber

2nd case from the left is a 270 win case
3rd case is a 270 win thats been sized to a crush fit in a 6.5 Gibbs rifle (notice the bulge in the neck, thats called a false shoulder and it holds the headspace while the case is fireformed
the case all the way on the left is a fireformed 6.5 Gibbs case (which is one of the 2% which split in the shoulder during fireforming)
The cases on the right are a loaded 270 win and a formed and loaded 6.5 Gibbs, pretty simple once ya understand how it works.
RR

[Bernie P.]

The routine depends on what your reforming.In my case I'm resizing some 30-06 Mil brass to .280 Rem.I need to be careful on setting the full length die just right due to the shorter 06 case to prevent misfires.After resizing I have what is called a "false shoulder".I then use starter loads to fire form the case' to 280 and the shoulder goes away.Other cartridges sometimes require more steps.You need to be specific what cases you're working with.

[bronko22000]

Bowhunter - I've done exactly the same thing when I had my 7mm TCU. You simply run the 223 brass into a 7mm TCU sizing die. You load these cases up with a moderate load and fire them in your 7mm TCU chambered weapon.
And unlike the 270 to 6.5 Gibbs above you very seldom have a case split. Brass is very ductile and its actually amazing how much it will shape itself to a chamber.