Hydraulic Decappers available anywhere?

How about this.
RCBS Berdan Decapping Tool 9525 - Adorama

The Swiss Rifles Message Board has a ton of information about loading Berdan Primed GP11 brass. I know that I've seen a video on a home made hydraulic decapper there.

I couldn't find it now, but did stumble on this picture in a thread about reloading GP11.

http://lacitroenbx19gt.com/photos/K11/cibles/desamorceur2.JPG

You might have to get inventive and make one. I suppose that you could use a shell holder, fill the case with water, insert a properly sized wood dowel, and smack it. The problem would be if the case became off center in the shell holder it would restrict the primer from coming out. The fellow who posted the picture has a more stable device to support the case. That sounds like fun on a hot summer day!

Buy a Whidden hydroform die for your cartridge and use a conventional shell holder.

And a mop…

Works relatively easily.

In theory, any seating or sizing die should be able to be modified to do what you’re wanting. Producing the piston would be up to you, but may not be so terribly complicated. I suppose many brands would need to use a sizing die.

Hydraulic primer removal in the outback. Clean water must be at a premium there:



Here's a description of how to use a standard sizing die to do it on a press. This was from a Swiss Rifles thread where someone posted a Youtube video. The video was "private" so I couldn't link to it. This was a post that followed it by whiz bang member "Parashooter". His stuff is pretty solid:

"Using a loading press and an ordinary expander for hydraulic decapping is nothing remotely new, nor is there anything special about the Lee tools for this job. Most regular sizing/expanding dies are perfectly usable. (First step is to remove the decapper/expander assembly and size the case. Then reinstall the assembly and back the die body out about a half inch - enough so the decapping pin doesn't hit the case interior. Fill a case with water and run it into the backed-off die. The expander serves as the hydraulic ram - and also expands the neck. Works like a champ with GP11 cases and my RCBS sizer. It's a little inconvenient with Lee dies, simply because removing/installing the decapping stem is a wrench job.)"

The volume of water which fits inside of a case is plenty to drive out berdan primers. My first post wasn’t a theory, it’s equipment I have used.

If you’re driving out primers, you have enough pressure differential inside the case which isn’t present outside of the case to also move your case walls and shoulders.

I experimented removing 7.62x39 Berdan primers several years ago, just curious (25-30 years ago). Simple, I turned a brass rod to just fit the case neck and set about dipping and smacking. No other parts except a shell holder on a 4x4 block. Worked OK but messy. In couldn't find any Berdan primers at the time so I figgered the experiment was a success and filed the info away for future use...

I googled "Hydraulic decapping tool for Berdan primed brass". I got mostly hits about RCBS "hook type" decapping tool (Over $90!), but there were some interesting threads abo home made hydraulic decapping...

I’ve wondered about rigging up something with an old air rifle action to do pneumatic decapping. I may try it yet

Atavar said:

I’ve wondered about rigging up something with an old air rifle action to do pneumatic decapping. I may try it yet

Click to expand...

That will be very dangerous. It will take more pressure than you think and when the primer comes loose you have a flying projectile. Plus all the excess gas pressure has to vent, just like setting off a round.

Water is the preferred method since it's not compressible. Once you get any movement pressure drops. There is a reason pressure vessels are pressured tested with water. Your not setting on a bomb. I've done extreme high pressure testing in well head equipment. 1 cuft of gas @ 30kpsi, catastrophic failure, is equivalent to 5 sticks of dynamite going off. I had special test chambers that I did all my HP testing in to take this without damage. We had to test with gas. Had an exotic liquid Nitrogen pup to compress the liquid to 5kpsi, the gasify it feed out big air drive pumps. We could go from 0 pressure to 15kpsi in 3 min. Used roughly 2000 gal of Liquid Nitrogen every 2-3 days when we were running.

Air over hydraulic and we can all get along?


What is the largest case you want to do?

I would probably do something not completely unlike my boost pump build.

1” seamless 4130 (wicks air craft sells if by the foot) and a small piston inside driven by a much larger pneumatic cylinder.

I would probably make it “window die” style so the case is dropped in when the piston is retracted. Once activated the piston passes the window and goes to work as soon as it’s past.



The base of the case (head stamp/rim) would be where the seal is, pressure would be on both the inside and outside of the body, so it shouldn’t change at all. Think of the case as a “check valve”. Need an orifice at the bottom as well as a seal, might try a faucet washer first but wouldn’t expect it to last very long but I know where a bag full of them are that I don’t have use for.

I would have the base IN water, the primers would fall into this tank and as the pneumatic ram came backup, it would suck water back into the hole the primer just fell out of and the flow of water would bring the case back past the window.

A continuous flow of water from the opposite side of the window fills for hydraulic and is the means of ejection. You just have to over come the water inserting the case. Shouldn’t take much, a tiny little giant pump would probably work.

It would work exactly like this, as far as decapping without blowing up the case.



Just with a production rate over 8/minute, no hammer vs hand involved and a lot less work.

How many of these do you have again?