View Full Version : GP11 decapping and berdan-priming

01-23-2007, 5:28 PM
I built a simplified hydraulic decapper(courtesy of surplusrifles.com) for the GP11 spent-brass: 1/2" pipe coupler, 3/8" nut, and 5/16" x 2" clevis pin (total $3.00). I don't even use the 1/2" pipe-sleeve, the water-spray was an exaggerated issue. The coupler and nut are used to build the brass-seat. The pin is the ram.

Fill up the case w/ water, hammer-tap the pin slightly to center, and then a 6" hammer drop/hit and you're done (the pin should only goes in 1/4" or so). When I got going, I was able to do 4 cases a minute.

Got some berdan primers over gunbroker.com for $55/2000 (include shipping). Seat them w/ lee hand-primer and I'm good to go (the rockchucker priming-cup is bit small)

Same setup will work for the berdan-primed 308 (or 7.62Nato) cases. I have too many 308 WIN cases, so I didn't bother.

01-23-2007, 5:56 PM
congrats tteng.
I'm reloading the prvi boxer brass but I've saved every gp11 brass for possible reloading. I'll have to look up the info. I'll also check out gunbrokers and see if there's anymore berdan primers. Hope u didn't buy'em all!:D

01-29-2007, 10:48 AM
Shot-off 50rd of reloaded-GP11 (41gr WC846, 168gr Speer GM) cartridges, and went through the K31 accurizing process as per swissrifles.com, last Saturdays at Chabot. There was no FTF, but I did noticed a slight delay on some of the cartridges going off, and I believe that's due to the primers not seated all the way (the firing pin was seating and then igniting the primer against the case anvil). The GP11 primer pocket is a little deep for the PMC berdan primers, but it's OK to seat it all the way (I was playing w/ various primer seat depth, but all rounds went off. So it's best to seat the primer all the way to ensure instantaneous ignition.)

About swissrifles.com's K31 accurizing method, I was able the get a 2" 5-shot (100yrd) group for this load (all the way from 3" group), and the process was very repeatable. So from now on I just have to work on my reload recipe to shrink it further.

01-29-2007, 1:29 PM
I got a couple of cases of GP11 that i shoot. I don't reload, but I save the brass to sell at the recycling center. If you want/need some, and yer in the San Leandro area, give me a holla and i'll sell you some cheap

at the momment, I only have around 150 cases in my bucket-o-brass, but that number is only going to grow...

01-29-2007, 3:25 PM
did u do the pillar bedding tteng?
I might try that 1of these days:)

fyi, for those interested on Prvi brass from Graf's; updated date of availability 2/28. Prices is up a few $.

fyi2; Graf's 50th aniversary sale is on. Phone orders only.

01-29-2007, 4:11 PM
No, I didn't glassbed/touch the stock at all.
I just follow Pierrer's accurizing steps.
1. Spacer-relief the front/rear stock-band so the barrels are not constrained.
2. Dead-tight the front action screw. Backoff the tang-screw 2/3 turn from dead-tight. Then shot off 5-shot group every 1/8 tightening turn. I was able to see a trend going w/ my grouping relative to my tang-screw position.

You'll need about 40-50 rds of consistant load to run this test (GP11 or your handload). I did shoot couple fouling-shots, but I don't know if it's necessary or not.

Chief..Can you PM me your price for your GP11 cases. Thanks.