Gewehr 88 Low Pressure -- What Should I Bump It To? - The Firearms Forum

Josh Smith · 11-12-2011, 11:52 PM

Hello,

My load for the Gewehr 88 with a bore that slugs 0.318" is as follows:

Winchester case formed from .30-06 Winchester case

0.318" 150 grain spitzer bullet

46.5 grains Varget

Federal large rifle primer

Now, I'm having signs of gas leakage around the neck. I'd like to bump it up a little bit to make that stop, but it's probably due to the "S" rethroating.

I don't remember the upper limit for the 7,92x57J cartridge, or for the rifle. I was thinking 40,000PSI, but am not sure. Could be 45,000 PSI. One is CUP.

I do believe I'll stick with 40,000 PSI though.

I was going to start bumping it a grain at a time, but I'm really not sure when to stop. I know that by the time it shows pressure signs I'll be exceeding the action design.

I'd love me a pressure gun, but since I don't have one, I'll have to take educated approximations from you all.

So, where do you suppose I should stop? What load would max at 40,000 PSI?

Thanks,

Josh

300 H&H · 11-13-2011, 05:37 PM

Josh,

Back in the day the wildcatters used to work up to maximum loads by measuring the case head for growth. If it is only 1/2 thousands bigger, some thing moved too much and the preasures are too high....This was of course using an action of more strength than yours. But I believe it still has merrit in your rifle. Watching for primer back out, and how hard the bolt lifts "can" be signs as well. Before trying how ever I would look high and low for an artical in a publication such as gun digest or shooters bible, as years ago some one may have written about the Gew 88, as many were around surplus here. Does yours have the barrel jacket? Military models usually do, but commercial sporters do not. There is an absoulute mountain of information that is not on the internet, and I am betting what you want isn't here. But I also believe it is out there on real paper, somewhere!

Regards, Kirk

Jim K · 11-13-2011, 08:18 PM

The original factory sporting loads for that caliber and that bullet approximate weight ran 40k psi, so I think I would stick to that pressure range. The rifles are stronger than some writers say, and routinely fired the 7.9 (8x57JS) military load after the chamber neck was reamed to allow the case neck room to expand, but there is no point in going beyond the original pressures for sporting purposes.

Jim

11-12-2011, 11:52 PM	#1
Josh Smith V.I.P. Member Join Date: Nov 2009 Location: Wabash IN Contributor Posts: 66	Gewehr 88 Low Pressure -- What Should I Bump It To? Hello, My load for the Gewehr 88 with a bore that slugs 0.318" is as follows: Winchester case formed from .30-06 Winchester case 0.318" 150 grain spitzer bullet 46.5 grains Varget Federal large rifle primer Now, I'm having signs of gas leakage around the neck. I'd like to bump it up a little bit to make that stop, but it's probably due to the "S" rethroating. I don't remember the upper limit for the 7,92x57J cartridge, or for the rifle. I was thinking 40,000PSI, but am not sure. Could be 45,000 PSI. One is CUP. I do believe I'll stick with 40,000 PSI though. I was going to start bumping it a grain at a time, but I'm really not sure when to stop. I know that by the time it shows pressure signs I'll be exceeding the action design. I'd love me a pressure gun, but since I don't have one, I'll have to take educated approximations from you all. So, where do you suppose I should stop? What load would max at 40,000 PSI? Thanks, Josh __________________ - Smith-Sights Adjustable Sights for the Mosin-Nagant - -->

11-13-2011, 05:37 PM	#2
300 H&H Advanced Senior Member Join Date: Mar 2007 Location: Iowa Posts: 1,803	Re: Gewehr 88 Low Pressure -- What Should I Bump It To? Josh, Back in the day the wildcatters used to work up to maximum loads by measuring the case head for growth. If it is only 1/2 thousands bigger, some thing moved too much and the preasures are too high....This was of course using an action of more strength than yours. But I believe it still has merrit in your rifle. Watching for primer back out, and how hard the bolt lifts "can" be signs as well. Before trying how ever I would look high and low for an artical in a publication such as gun digest or shooters bible, as years ago some one may have written about the Gew 88, as many were around surplus here. Does yours have the barrel jacket? Military models usually do, but commercial sporters do not. There is an absoulute mountain of information that is not on the internet, and I am betting what you want isn't here. But I also believe it is out there on real paper, somewhere! Regards, Kirk

11-13-2011, 08:18 PM	#3
Jim K Advanced Senior Member Join Date: Dec 2009 Posts: 6,408	Re: Gewehr 88 Low Pressure -- What Should I Bump It To? The original factory sporting loads for that caliber and that bullet approximate weight ran 40k psi, so I think I would stick to that pressure range. The rifles are stronger than some writers say, and routinely fired the 7.9 (8x57JS) military load after the chamber neck was reamed to allow the case neck room to expand, but there is no point in going beyond the original pressures for sporting purposes. Jim