Hydro forming

[txgunner00]

No, you don't need to pull it forward. Just rotate it about 15 degrees so the ports don't line up.

[hodi]

txgunner00, it looks like I should be able to just loosen a couple of allen head screws in the gas block to loosen it. It is the picatinny rail type. I was afraid that I would bend the gas tube turning it, but I guess 15 degrees isn't very far.

[no cigar]

Sorry to bump such an old thread. txgunner, I was curious about having a look at the tool you use to form that brass in a press. Also could this forming be done with the primers still in?

Also, I'm trying to grasp the idea of how this forms the brass with basically driving a drill bit down into the mouth of the brass... So the pressure inside the case which is displaced by water and a tad bit of air forces it to expand slightly?

Thanks!

[txgunner00]

I haven't used this method in quite a while so I'll try to remember the details as best as I can. The tool was made from a Hornady sizing die with the expander stem and collet removed, a bolt that fit where the collet threads in and a piece of hardened drill rod (1/4" I think). Basically you are creating a piston that, when struck with a hammer, forces water into the case and expands the brass into the sizing die. Primers must be left in and, if you look closely at the picture, a plug must be installed in the shell holder to prevent the primer from being blown out when forming. I did a quick sketch that hopefully will help illustrate.

hydro die.jpg

It works OK. The hardness of the brass really makes a difference on how well it forms. Winchester and other soft cases form nicely but hard cases such as IMI don't form into the corners very well. Your first full power firing will take care of it though.

I don't use this method anymore because I fire form with sub-sonic loads. You can find info on that in some of my other threads.