Comments Sought for Gew 88 Conversion

[CASEC]

As some of you know I am on a continuing (and maybe a little pointless) quest to fix the ills associated with the Gew 88 Commission Rifle. The primary shortcoming of this weapon being its poor gas handling capabilities in the event of a case head separation.

I recently purchased a Gew. 88 (Kar 88) that some long forgotten smith modified by drilling a small hole through the the bottom of the receiver and into the bolt lug recess. The apparent idea was to vent pressure into the magazine in the case of a case head failure.

A design feature of this rifle is a non-rotating bolt head. The first and most widely used design of this bolt head included a recess in the bolt head the depth of the cartridge rim.

A second and much rarer bolt head omitted the the bottom portion of the ring formed by the recess so that the bolt head recess is a half circle.

Now for the modification.

I am thinking of using the half circle bolt head design and drilling a hole through the bottom of the receiver into the bolt head recess as opposed to the bolt lug recess. This would appear to provide the most direct path to vent escaping gas in the event of a case head failure.

What does everyone think?

This is not an idle question btw. I have had a few reproduction bolt heads manufactured in past and am preparing to have a second run made. I am visiting the manufacturing facility in May, and need to send my sample in fairly soon. I just paid an arm and a leg for the more rare of the two types of bolt heads and don't want to ship it off if we determine there is a flaw in my plan.

Kind Regards and Thanks, CASEC

[Oldmandan]

What does everyone think?

I think you're crazy! What the hell is this costing you?

[CASEC]

I think you're crazy! What the hell is this costing you?

More than is justified or prudent

[ptoguy2002]

More than is justified or prudent

That makes it a hobby.
.
I don't know much about the Gew88s, but there are good pointers about drilling scope mount holes in Mauser receivers in one of the Mauser smith books. Where to drill and where not to drill, I suppose the concepts would translate.
IMHO, drilling the bottom would vent gas into the stock and still cause it to come apart. Can't you go up?
Buy a cheap Gew88 and test it yourself..........be careful though.

[CASEC]

That makes it a hobby.
.
I don't know much about the Gew88s, but there are good pointers about drilling scope mount holes in Mauser receivers in one of the Mauser smith books. Where to drill and where not to drill, I suppose the concepts would translate.
IMHO, drilling the bottom would vent gas into the stock and still cause it to come apart. Can't you go up?
Buy a cheap Gew88 and test it yourself..........be careful though.

Good idea!
How do I replicate a case head separation?

[CASEC]

That makes it a hobby.
.
I don't know much about the Gew88s, but there are good pointers about drilling scope mount holes in Mauser receivers in one of the Mauser smith books. Where to drill and where not to drill, I suppose the concepts would translate.
IMHO, drilling the bottom would vent gas into the stock and still cause it to come apart. Can't you go up?
Buy a cheap Gew88 and test it yourself..........be careful though.

Good idea!
How do I replicate a case head separation?

Also I'm hopeful I sell enough of the parts I have made to offset cost. Last 10 I had made sold in 3 days. Still, I really do it out of a love of the weapon and a desire to get the 2500 that were imported as basket cases back on the firing line.

Also of note the magazine well runs under the bolt lug recess so it should vent there.

[kcstott]

Good idea!
How do I replicate a case head separation?

P.O. Ackley tested rifles and there was no simulating anything.
He overloaded cases to prove action strength, and weekened cases so case head separation would occur.

He ruined a lot of rifles in the process but his book that contain the test information are considered the gold standard for action stregth

[CASEC]

So how do I weaken the case? Score it perhaps, or cut through with a saw?

[Springfield45]

So how do I weaken the case? Score it perhaps, or cut through with a saw?

You could drill a small hole in front of the rim. You may be about to extract the shell as normal after while still duplicating the gases of a ruptured case.

[CASEC]

Now I need a remote location and a tractor tire to tie this experiment to.

[kcstott]

he use to slice cases in half, cut two cases in slightly different spots,

you take the rear piece of one and the front piece of the other so the legths over lap then you sand both square and to correct length.
then case is separated but will hold together long enough to see where the gas vents.

Seriously though you need about five actions to prove out max pressure and gas handling.

My recommendation for a conversion. weld the but plate to a base plate and run a lamp cord through it to the lamp fixture you welded to the barrel.
lacquer it up and call it good.

That would be an Ideal use for a mosin