View Full Version : Hydroforming the 25Rem

11-21-2015, 02:05 PM
I mentioned I was going to make a thread on Hydroforming. Seems folks fire form some of the brass they convert, but since I don't have chamberings in a lot of what I convert I came up with my own way of Hydroforming.

Let's face it, there are companies that do offer Hydroforming dies but they aren't cheap. Not only that what they provide is on the "UNIQUE" side, so if something gets damaged your stuck until you order a new part and you get to pay there price once again.

What I did was get a lathe, and in my area those are very scarce, kinda like going Snipe hunting. Once I got the lathe my mind started to come up with all kinds of things to make, and this is but a fraction of it.

First I made a plug, this plug blocks the hole in the shell holder, but....it has to be big enough so when it's put in the press it wont just fall through the slot in the ram. And folks....You have to leave the primer in the case.


I made it to fit kinda snug so getting it in the ram takes a little persuasion .


Next I made what I call the plunger, it's nothing more than a grade"8" bolt machined to precisely fit the neck. And the neck is measured "AFTER" it's been run through the die. I didn't make it to just simply "drop in" the neck, but it has a slight resistance to it. It needs to be done precisely and polished to an 8 finish, which is almost as smooth as glass.The de-capping rod is removed from the die, this must be done because you need to make a guide to keep things inline with everything.


The so-called guide is nothing more than a machined down bolt with the same thread as the die, and I just used the right size drill to bore the hole. Here's a picture of the rod and guide and notice how everything is inline, very little wobble between the rod and the guide. I fill the case with water till it's just below the case mouth, them put it in the shell holder and run it up in the die with the plunger removed. I insert the plunger "AFTER" the case is in the die, and give it 2 whacks with the brass hammer.


Here's an older picture of the before and after. Notice the difference in the shoulder location, and the angle is different. It only takes me a couple of good whacks with my brass hammer to form the brass. Also take note that I have the press on a dedicated "METAL" bench, it was my old radial armsaw table. Trust me if you try something like this on a table with something on it you'll be surprised real quick how much stuff just falls off the table.


After Hydroforming I bring them in the shop and machine the head to spec. A person needs to be in control doing this, so since nobody makes a case gauge for these cases I made my own. And with some help from other members here, they sent me some factory (HARD TO FIND) cases that I based my gauge from. There's something called a gauge dimension that must be held and monitored at all times, so I wouldn't recommend trying something like this unless you have the proper tools. This is just a picture of a different conversion, but it's a good visual aid for folks.


11-21-2015, 02:12 PM
If anyone attempts to make this here's a couple words about it. Be prepared to remove about .010 from the base of the sizer die. I found that LEE dies just aren't cut out for this type of work. And water does get sprayed when that hammer hits the plunger..

Also stick with the same head stamp, there's small variations in brass thickness which requires a different plunger of a slightly different size to be made.

Another thing about forming in this manner. When I make the necks smaller, they grow in length, and just the opposite happens if I make the neck larger like the 32Rem.

Also if folks were to make any of the AI cases, like using 280 factory brass for the 280AI they'll get a bit shorter.

Add on edits: When I say I made the plunger to fit the neck "AFTER" I ran it through the die, it refers to it being run through the die with the de-capper rod removed. That must be done in that manner since running the case through the expander will expand the neck.

11-21-2015, 02:48 PM
That's a slick setup. As always, thanks for sharing. I really need to buy a lathe and tooling for it.

11-21-2015, 04:36 PM
Here's another picture of another conversion, the 225Win case. The 30-30 parent case shoulder/gauge dimension is .090 shorter, and I used the same technique on those as above.


11-22-2015, 04:07 AM
Looks like a very practical system. I will try to remember this.


11-29-2015, 02:21 PM
On this particular form operation, I'm reforming the shoulder.

01-19-2018, 07:45 PM
Hornady will make you a hydroforming die for just about any conversion. I sprayed a lot of water and spent a lot of money on cheaper solutions before I let the pros make me a die that finally really worked.