What is it?

[dubber123]

Hello all, I have an old Mauser that a friend owns, and I am trying to determine what caliber it is. The receiver ring is stamped "Amberg 1918". The serial # is 1327, and the barrel matches the receiver. Now according to all I read online, this should be in one variation or other of 8MM Mauser. BUT, a partial slug of the muzzle gives me .292". Now thats really tight for an 8mm, and really loose for a 7mm. I know they made a .318" bore 8mm, but even those #'s don't jive. Anyone have a theory? Thanks.

[Texas by God]

It could be a Gew98 rifle or a 98A carbine with that date. If it is long barreled with a "roller coaster" rear sight it's probably a Gewehr 98. Amberg was a government arsenal. By 1918 the switch to 8x57S(.323") had been complete for years so that is most likely what it is. The 98A is shorter, with a full length stock, a stacking rod nose cap, and a small ring 98 action. Do a full barrel slug and see what you get. I can't imagine it being chambered in 8x57J(.318")- but Mauser Land is full of surprises. We like pictures:-)
TbG

[junkbug]

Is it a sporting type rifle? My first guess would be a WWI surplus GEW 98 or KAR 98a that has been re-barreled and sporterized to 7mm Mauser, a long time ago. The 7mm Mauser was much more available in the USA after WWI.

It could also simply be re-barreled with a surplus 7mm Mauser barrel that looked "close enough" to a former owner.

The muzzle crown is the first place to show wear. It could easily be wallowed out to the measurement you reported by improper cleaning for years on end.

[dubber123]

It is a Gew 98. The bore looks very good, with sharp rifling right to the end. It is a long barreled rifle with the "roller coaster" rear sight. I will do a full slug, but i'm betting I get a similar #, and .292" is a long ways off the .284" of a 7mm, which is what has me buffaloed. Thanks for the ideas so far.

[El Bibliotecario]

Is the barrel serial numbered to the receiver? If not, that might answer your question.

[junkbug]

Many military 7mm Mausers, even when brand spanking new, are closer to .287-.288" than .284".

[john.k]

A very simple test is to drop a 308 bullet in the muzzle....it will probably fall thru.....which means the measuring is haywire.............

[Earlwb]

You really should get a chamber cast done and also slug the bore to figure out what you have. No sense taking chances or risking anyone to just shooting something through it based on a wild guess.

[dubber123]

I slugged it and did a throat slug too, came out to .2885", so as junkbug mentioned, seems to be a run of the mill loose 7mm. Thanks for the information.

[Texas by God]

So here we go. How is a wartime(1918) Amberg Arsenal matching number barrel and action Gew 98 - a 7x57 mm? The only other Mauser with the Lang Vizier "roller coaster" rear sight- as far as I know- is the Peruvian 1909 in 7.65x53 Mauser. Cue Twilight Zone music....
We need pics; this is verrry interesting!

[koehn,jim]

NOE makes some oversize molds that should work in it.

[LynC2]

If it really is an unaltered matching number rifle in 7mm, it may be something desirable for a Mauser collector. Something to consider.☺

[EDG]

Definitely not true.
While the 7.92X57J ammo used .318 bullets the groove diameters were about .320 to .321. That is how they got away with shooting S type ammo in all those 1905 conversions (about 1,000,000 rifles or more) performed on the GEW88s.

The only true .318 barrels I have ever read about were GEW 88s rebarreled for some South American country by the Czechs with new Czech barrels. I slugged both my KAR88 and GEW88 and both are .3205 groove diameter. The KAR88 was never converted to use the stripper clip ammo so it was still in the original as built configuration. The GEW88 was updated to the 1905 configuration with the stripper clip guides and the notched receiver before it was supplied to the Turks....


The early 98 Mausers were .318 groove diameter. When converted to the .323 design all they did was cut the grooves deeper, so the bore diameter was not changed.
The only 98 Mausers from Amberg were 8x57.
A chamber/throat cast w/cerrosafe (Brownells) would tell you what you have.

As I recall from the Collector Grade books on Mausers, the bore diameter of both the J (really I) and S bore guns was the same. Only the groove diameter varied. (?) Frequently writers are sloppy about "bore diameter" when what they mean is groove diameter. If an "S bore" rifle really had a .323 bore, a .323 bullet would rattle down it. It has .323 grooves as we "lead shooters" know that when a bore is slugged and you measure the slug, you are measuring the dimension across the bottom of the grooves.

I once owned a fancy German inter-war sporter in 8x60 that had .318 grooves while the ammo was .323. Theory was it increased pressure, hence performance. With 232 gr H Mantle bullets it kicked the snot out of you.
The 8X60 came about to be able to use all the WW I 98s w/o breaking the treaty rules of WW I.

Many that came here became 8x63 (or so) know as the 8mm-06, a serious thumper.

[dubber123]

So here we go. How is a wartime(1918) Amberg Arsenal matching number barrel and action Gew 98 - a 7x57 mm? The only other Mauser with the Lang Vizier "roller coaster" rear sight- as far as I know- is the Peruvian 1909 in 7.65x53 Mauser. Cue Twilight Zone music....
We need pics; this is verrry interesting!

While the same # appears on the receiver ring and barrel, something seems "off" The font doesn't look like a home gunsmith stamped it, but doesn't look quite factory either. I'm betting it was rebarreled at some point in its life. I will try and get some pics up this weekend.

[Multigunner]

Spain bought a number of WW1 surplus GEW98 rifles that had been converted to 7mm by sleeving the bores and re-cutting the chambers.
If not sleeved it may have been re-barreled instead.
Several Central European countries used 98 type actions barreled in 7mm. IIRC Serbia bought DWM made 98A short rifles re-barreled for the 7mm.