GEW 88 Commission Rifle Chamber Question

[clement1]

ARE THE EXTERIOR DIMENSIONS OF AN 8X57 J (The original 8mm ammo for a GEW 88 Commission rifle) DIFFERENT THAN A modern 7.92 8MM CARTRIDGE. I would like to find out why a standard 8mm cartridge BRASS, not loaded ammo, would not fit in my Gew 88 commission rifle. Now I know that the ammo is different...I know about I and J and JS ammo...318 vs .323, etc (please no further info needed on that topic thank you)...But my question is...Why would a round not fully chamber...I can get a round into the chamber up to about .235 from the end of the brass...no bullet in the brass...it just won't go any further, you can not close the bolt on it. Is it becasue the diameter of the bullet is .323 and the exterior of the case mouth is too wide for the chamber??...if so why do 323 diam. bullets regularly fire in the GEW 88...is my chamber irregular, or could it have shrunk (I know this is ridiculous)...so what are the plausible reasons for a modern 8x57 JS or 7.92 8mm cartridge not seating all the way in the chamber. Unfortunately I have not been able to find any original 8x57 I/J ammo.
Thanks.

 

[shotgunjoel]

Is it fired brass? If so, the brass would be expanded to seal into the chamber in which it was fired. That would be my guess for your issue.

 

[shotgunjoel]

This is from the wikipedia page on the 1888, look under "Modifications"

The more important change was a wider chamber throat to take the thicker brass of the new cartridge. Rifles with this change have the receiver marked with a large "S".

It would seem that the newer/modern cartridges are a different size. Does your rifle have the S stamping?

 

[dirtyjim]

ARE THE EXTERIOR DIMENSIONS OF AN 8X57 J (The original 8mm ammo for a GEW 88 Commission rifle) DIFFERENT THAN A modern 7.92 8MM CARTRIDGE

yes the neck on a modern 8x57 is .005" larger.
depending on the neck thickness of the brass some will chamber & some wont.

if so why do 323 diam. bullets regularly fire in the GEW 88...

they fire in chambers than have had the neck & throat cut for a .323 diameter bullet.
just call ptg for a 8mm neck & throat reamer then recut the neck & throat, problem solved.