Warning for users of hydraulic method of removing Berdan primers on GP11 cases
- Thread starter diopter
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Which pic is that one?
Had another look. I was wrong. The brass IS being deformed into the primer pocket in all the cases.
At first glance, I thought some of the cases had been manufactured with a single flash hole. This is a system used in some Berdan primed cases.
At first glance, I thought some of the cases had been manufactured with a single flash hole. This is a system used in some Berdan primed cases.
tungngroove2000
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I need me one of those Berdan primer tools. Anybody out there making them? I have the hydraulic setup and would much prefer this method. PM me if you can make something like that work. Thanks
I have never seen this before. I reload GP11 but only cases 1982 and newer. Some have been reloaded more that 7 times.
I noticed quite some time ago that there was a design change in 1982 to the GP11 anvil shape and location of the flash holes.
1981 and prior have a smaller diameter anvil with flash holes right beside the anvil. Anvil is shaped like this: U
1982 and later have the larger diameter anvil with flash holes near the pocket perimeter. The anvil is shaped more like this: )
It's my gut feeling that the later 82+ brass is more robust when in comes to the pressures generated using the hydraulic method.
Thanks to the OP for alerting us to this potential problem. I will now keep a close eye for anvil failures...
I noticed quite some time ago that there was a design change in 1982 to the GP11 anvil shape and location of the flash holes.
1981 and prior have a smaller diameter anvil with flash holes right beside the anvil. Anvil is shaped like this: U
1982 and later have the larger diameter anvil with flash holes near the pocket perimeter. The anvil is shaped more like this: )
It's my gut feeling that the later 82+ brass is more robust when in comes to the pressures generated using the hydraulic method.
Thanks to the OP for alerting us to this potential problem. I will now keep a close eye for anvil failures...
I was thinking of converting some to boxer. The process looks time consuming but simple enough. Spend the time to get it done once and then just reload as boxer primed brass. I was going to try 20, see how long it takes, and see if it's worth doing 100 or so or to just buy some Prvi brass. I'm cheap and have time to spare.
I have looked into this and unless you have access to a high pressure swaging press and specialized tooling, you are wasting your time. The primer pocket of GP11 (and all NATO Berdan cases) has a larger outer diameter than the O.D. of a Large Rifle Boxer Primer.
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I'm well aware of the differences in primer and pocket sizes. And if I learn something from the process, even if it doesn't work, I'd hardly call it wasting my time.
All the tutorials I've looked at use a steel rod, a hammer, and a ball bearing. It reduces the edge of the primer pocket to smaller than a LR boxer primer. You then use an RCBS primer pocket swage tool to bring it to normal size. Even though only the edge is holding the primer instead of the entire depth of the pocket, there are various reports of over a half dozen full power loadings without gas leakage or anything else. Then you again just use a hammer and rods to crush the berdan anvil which fills the flash holes, drill a new flash hole, and you're good to go. I just don't know how much time it'll take per case.
I was going to start with greatly reduced pressure cast loads and work up to regular loads (regular based on US manuals which is significantly below original GP11 loadings).
I use Privi 7.5x55 brass, and .284Win brass re-sized to 7.5x55 case dimension for Boxer primers.
Also reload GP11 with Berdan primers.
Has no intention of even attempting to convert Berdan brass to Boxer with my arthritic hands.
Also reload GP11 with Berdan primers.
Has no intention of even attempting to convert Berdan brass to Boxer with my arthritic hands.
This is how GP11 flash holes should look.
Hydraulic method is distorting the case head in these two pictures.
Parashooter pics and homemade Berdan tool.
Impossible. If the hydrolic method formed the brass that much, why wouldn`t it blow out the side of the case head where it`s weaker.
That flaw was made during the manufacturing process.
I agree. It's been my experience that the case neck splits from, the hydraulic pressure on really stuck primers. I use a hammer and cut off precision screwdriver through the case mouth to pound out the primers through a flash hole. With a little practice it's pretty quick and easy to find one of the holes by feel and I've never punched a hole in a primer. They always come out. I buy the screwdriver sets to sacrifice from the dollar store as they will bend and break occasionally when being beat with a hammer.
That's the web and case head area, the strongest part of the case. And that doesn't explain the anvil and flash hole's being in the wrong place
