WWII Germany rethroats to accept .311 in

[snookdock]

I read that in the bad times of WWII, Germany rethroated some rifles to accept a larger bullet. I do not remember the sizes, but I recall something like using .311 ammo in a .308 bore.

The idea was to give the bigger bullets a running start and thereby avoiding a blow up. If true, it would have to be a field expedience as I'm sure any German gunsmith must have done this kicking and screaming.

 

[Father Knows Best]

Sounds fishy to me. The standard German rifle of WWII was the k98k Mauser, and it was chambered for the 8mm Mauser cartridge. It has a bore diameter if .323 -- LARGER than .308. The standard German machine guns were also 8mm. So what firearms were .308?

 

[snookdock]

This could have been told to me by the guy who said

This could have been told to me by the guy who said to go ahead and try a .308 in a .30-06.

Sometime ago I was had. However I poke fun, I don't play jokes with a man's tools or his life.

 

[DMK]

Finland used a smaller bore before the war, then went to a .311 bore and marked these barrels with a "D". I believe they just did it for ammo compatability with Russian ammo though.

 

[Jim Watson]

You can hear some strange things. And you are about a war off.

In 1888 Germany went smokeless powder with the 8x57J shooting a roundnose .318" bullet down a corresponding barrel, maybe .320" because the Europeans like to have someplace for the metal displaced by the rifling to go. In 1905 they watched what the French were doing with spitzer bullets at long range and went to a pointed bullet .323" in diameter, calling the new version 8x57JS. Naturally, they had to build guns with barrels large enough to take it. I don't know why they felt they needed to enlarge the bullet by .005" while making it lighter and pointier, but they did.

So there they sat with many old rifles made for the .318" bullets that they needed to get some use out of. Rather than go to the expense of rebarreling the old '88s they just ran in a reamer which enlarged the chamber neck so the brass could expand to release the larger bullet and tapered the throat to feed it gradually into the tight bore. Stamped an "S" on the action to indicate the change. Some of them also got a magazine modification so they could be loaded with the '98's stripper clips instead of the original en-bloc clips.
The more modern 1898-1904 rifles with '98 actions were also converted and the sights changed to match the trajectory of the new ammo.

 

[deadin]

Jim,
I believe that something similar was done with the Austrian Steyr Mannlicher Straight Pull originally in 8x50R.

Dean

 

[snookdock]

thank you for clearing this up

It is amazing how things change in just 115 years. I heard this over thirty years ago and the person who told me may have gotten it from his grandfather. Time dims all things.
Ken

 

[Jim Watson]

Dean,

Best I recall, the Austrians converted M95 straight pull 8x50R to 8x56R as used by Hungary. Enough that the Germans kept them making ammo after the Anschluss. Smith says Yugoslavia converted some to 8x57, too.

 

[jefnvk]

I believe the M95's were rebarreled altogether. Germany made ammo for them (or at least stamped the eagles on all of the ammo) during WWII, as that was Austria's battle rifle. Yugoslavia did convert them to 8mm Mauser, to save on ammo costs.

 

[Vern Humphrey]

Naturally, they had to build guns with barrels large enough to take it. I don't know why they felt they needed to enlarge the bullet by .005" while making it lighter and pointier, but they did.

The original "8mm" barrels were deliberately oversize -- bullet size was less than groove diameter. The idea was to allow some gas blow-by becuse of the rather erratic powders used. Powder got better, and the blow-by was eroding barrels. They increased the bullet diameter to match groove diameter.

The problem with older 8mms is not that they have too small a bore diameter, but that they are throated for the smaller diameter bullet. To safely shoot a modern 8X57 in these barrels, you need to open up the neck and throat to modern dimensions.

 

[Cosmoline]

I believe the M95's were rebarreled altogether.

That is also my undestanding. The new M-95 spitzers came in entirely new 8x56R cartridges that replaced the old 8x50R Mannlicher.

 

[Jim Watson]

The original "8mm" barrels were deliberately oversize -- bullet size was less than groove diameter. The idea was to allow some gas blow-by becuse of the rather erratic powders used. Powder got better, and the blow-by was eroding barrels. They increased the bullet diameter to match groove diameter.

My recollection is that J-bore rifles had .320"-.321" barrels for their .318" bullets. "S" bore is .323"-.324" for .323" bullets. The bore diameter was always .311", the later guns just had deeper grooves. Per Ken Waters.
As I said, I have seen references to European practice of making barrels of larger groove diameter than bullet diameter to allow for metal displacement. The intentional blowby business is a new one to me.

 

[cracked butt]

Out of the dozen or so 8x57 rifles that I slugged the bore on, the grooves ranges from .3235-.325."the average seems to be about .324" and as Jim W above said, the bores are .311"

Quote:
Originally Posted by jefnvk
I believe the M95's were rebarreled altogether.

That is also my undestanding. The new M-95 spitzers came in entirely new 8x56R cartridges that replaced the old 8x50R Mannlicher.

I've seen a few of these rifles chambered in 8x57, they do exist. Rebarreling would probably be necessary as the rifle was converted from a rimmed to a rimless cartridge and the fact that the 8x56R bullets have a .329" diameter.