Hydroforming!!!

[Festeraxp]

Hey everyone,
Anyone have experience hydroforming. Specially 6.5 grendel. Do any other calibers do this too? Also where and how long did it take if you have one the get the die. Thanks in advance.

 

[Rocketmandb]

I got a hydroforming die and played with it for my 300 PRC when I was fireforming 8x68S brass. It worked okay, but I couldn't get something that still didn't require a forming shot afterward. I didn't continue with it.

 

[Vodak]

TLDR-
Fireform if you can. The Grendel still shoots pretty darn well with fireforming loads and the results are in my opinion better.
I used to hydroform 7.62x39 for Grendel back in the old days before brass was available. Admittedly I didn’t have anything close to an ideal set up, but I managed to make it work.
I tried a couple methods of sealing the primer pocket with various success. Spent primer and a lathe turned solid faced shell holder. Spent primer and scrap of metal on top of a shell holder. Scrap of rubber pressed into place with an RCBS primer swaging tool. None were great but all worked. Now you can buy o-ring sealed plugs.
Then I would fill the brass just past the shoulder into the neck with water, run the shell into the sizing die, drop a punch turned as close to the size of the neck ID in the die, and smack it with a hammer a couple of times. Take a tiny shower, lower press ram, punch case out with smaller diameter punch. Set up decapping stem and open the neck back up/ remove spent primers. Look over disappointing rounded shoulders.
Load up light powder charge and a bullet and go fire form like I should have in the first place.
I get that components are a precious commodity right now, but in my opinion it’s worth it unless you really can’t afford to use them up.

 

[MakeSawdust]

Without writing a book, the trick is to form them long and size the shoulder back to the correct datum measurement. That will square up the rounded shoulders. I have hydroformed a metric shit ton of 243 ai. I prefer to fire form if I can do it during barrel break in or something where I don't feel like I am wasting barrel life.

 

[Vodak]

Without writing a book, the trick is to form them long and size the shoulder back to the correct datum measurement. That will square up the rounded shoulders. I have hydroformed a metric shit ton of 243 ai. I prefer to fire form if I can do it during barrel break in or something where I don't feel like I am wasting barrel life.

This makes perfect sense, I wish it had occurred to me when I was doing it. I still have a couple hundred Lapua made KP 7.62x39 cases, and most of an unloved upper. Maybe I'll run some more, or get a 6mm Arc or ARTubo barrel and play around.
Do you use a die specifically for hydroforming, or use a sizing die set long? If you're setting a sizing die long, by how much, and do you ever see issues with bulging at the case web?

 

[MakeSawdust]

This makes perfect sense, I wish it had occurred to me when I was doing it. I still have a couple hundred Lapua made KP 7.62x39 cases, and most of an unloved upper. Maybe I'll run some more, or get a 6mm Arc or ARTubo barrel and play around.
Do you use a die specifically for hydroforming, or use a sizing die set long? If you're setting a sizing die long, by how much, and do you ever see issues with bulging at the case web?

I use a sizing die set long. I honestly don't know how long. It is pretty long, sometimes in the .050-.100" range. I would say closer to the .050" range. I get zero swelling at the web. My hydroformed cases are a couple thou smaller than my chamber and measure the same at the web as the virgin brass.