Gew88 Max Loads?

[Josh Smith]

Hello,

I've been handloading my Gewehr 88. It is "S" marked but I still prefer 0.318" bullets, and they actually seem to give superior accuracy. I'm going to slug it again, but it appears the bore is pretty tight. Came out to 0.3165" last time, but I've shot fouling out since.

Anyway, I'm using Varget. It has become my go-to powder for milsurps, especially the 7.62x54R and 7.9x57J.

Now, as I understand it, the max operating pressure for a Gewehr 88 is 45,000 CUP. According to Hodgdon, 45.5 grains, the starting load, produces around 37,500 CUP with the max load producing 49,000 CUP. This is with a 150grn bullet.

Now, I'm running 46.5 grains of Varget. I was thinking I had low pressure signs in my Remington cases. After making some cases from Winchester .30-06, I found that the tolerances in the Remington cases were not in spec, so I trashed them.

Any guesses as to the pressure I'm running?

I'd like to keep below max pressure, or, in other words, I'd like to have a new minimum and maximum to work with, maximum being maybe 44,900 CUP or thereabouts.

Data listed by Hornady has their minimum as 43.5 grains but no pressure listing.

This sounds like a good starting load for the 7,9x57J, though. What do you think?

Should I just start again at 43.5 grains and work my way up? When should I stop?

My only goal is to find maximum precision in a given range. For example, if I use 43.5 grains to start and consider 47 grains to be max, then I won't go past 47 grains.

For comparison, the original J load was a 0.318" bullet pushed by Poudre B (can't find a burn rate on that; a burn rate for this powder would help a LOT). The bullet was cupro-nickel jacketed, 227 grains, and pushed to 2100fps.

Opinions would be appreciated!

Thanks,

Josh

[Burrhead]

Josh, with a rifle as old as this one and you're using data that is for a rifle of a modern design and a different bore diameter I'd practice some caution in my loading for the rifle. We can't assume that your chamber pressures are going to be the same for a .318 bore, they may be simular but that would be as far as I'd go on my assumptions with this. Don't try working up to the maximum of the rifle I'd respect her and only shoot moderate loads in her. If you got good accuracy I'd be happy and stop there. Now you might on an occasion push it a little but I'd be very careful and only occasionally. The last thing you want to do is to try and dodge a bolt coming apart or worse a receiver giving away.
So start at the the minimum and work up just till you get the cartridge to seal properly and "NO Pressure Signs" respect that margin of safety and be happy with it. If you have good head space and the primers are backing out then creep up in your charge. Pay attention to that bolt when opening if it's getting stiff then your pushing too much pressure same with really flat primers and look at those heads for any sign of bulging. If the rifle is shooting a good group then settle for that load. Another thing sense you don't really know the burn rate of the original powder and you aren't happy with what your getting try another powder. My 1889 Schmidt Rubin shoots best with IMR-3031. I picked this as it gave me good enough accuracy and I got good case seal in the chamber (no blow back of gas around the bolt) as well as no stiff bolt symptoms.
Hope this helps
Burrhead