Original C-96 Carbine. Large Ring Hammers with 14.5" barrels and conventional (non-Flatside)
frames are by far the most common variant of the original Mauser-made Carbines.
(I don't have a good photo so I cribbed this one from Erickson & Pate)
The important thing to realize about C-96 Carbines is that most of them weren't made by Mauser. The vast majority (at least nine out of ten, probably more) extant today are "reproductions" or "replicas" - extensive reworks of original Mauser pistols - made long after Mauser itself gave up on the carbine design.
Perhaps because the 7.63mm cartridge is pretty feeble for a rifle round, the carbine was not a sales success for Mauser. Only about 1100 were made, all of them before the start of the Stable Production Period. The earliest Carbines were Cone Hammers. Oddly enough, most of those were Flatsides - note that Cone Hammer pistols appeared with Flatside frames only on special order.
About 100 Cone Hammer Carbines were made, nearly all of them Flatsides. Those were followed by some 200 Large Ring Hammer Flatsides. Most Carbines to that point had 11.75 inch barrels. The standard barrel length then increased to 14.5 inches. Something around 600 Large Ring Hammers with conventional (non-flat) frames and the new longer barrels were made, followed by about 140 Small Ring Hammers with the same barrels and, of course, conventional frames.
The Carbine was one of those experiments which Mauser dropped for good at the start of the Stable Production Period. So in common with the pistols of the Early Production Period, Carbine design features were all over the place as Mauser experimented, searching for something which would actually sell. Despite this variety, some generalizations are possible.
All Mauser-made carbines had -
• 10-shot fixed magazines
• unmilled side rails (one or two prototypes may have had milled rails, like the pistols)
• a removable buttstock dovetailed to the frame (so that the carbine, lacking a grip on the frame, could not be fired as a pistol when the stock was removed)
Most had -
• 500 meter sights
• 11.8 inch (300mm) barrels
• 14.5 inch (370mm) barrels
Some (undoubtedly special orders) had -
• checkered wood
• fluted barrels
• barrel ribs
No Mauser-made carbines had -
• a MAUSER banner on the frame (this appeared on pistols some fifteen or twenty years after the carbine's demise)
• the New Safety or Universal Safety (ditto)
Standard pistols converted to carbines appeared shortly after World War One, and continue to appear today. A considerable number seem to have been converted in China about twenty years ago, and were sold in the US by, mainly, Navy Arms. Navy's sales literature signified reproductions or replicas by putting the name in quotes - i.e., "Mauser Carbine" signified a conversion of something else into a gun which looked a bit like an original Mauser Carbine. So Navy was flogging replicas, not actual fakes, although exactly what the customer was buying could have been stated a bit more clearly. But today, far too many of these "Mauser Carbines" are being sold as Mauser originals. The major difference is that the repros are worth something in the low three figures, versus the low five figures for originals.
Quick recognition features of fakes
• Barrels - The "repros" almost always have barrels just over 16 inches long. This is to avoid the National Firearms Act's special treatment of "short-barrelled rifles". In the US, a rifle (defined as a rifled shoulder arm) with a short barrel must be registered as an "NFA Weapon", which involves a bunch of forms and a $200 transfer tax. It's do-able, but a major pain in the crank.
Note that original Mauser-made carbines, despite their short barrels, have been excluded from the NFA, and are not "NFA Weapons". They are ordinary "Curios & Relics". See the Firearms Curios or Relics List, 1972-2001, Sec. III. However, fake or replica Carbines, being new guns (even if built partially of old parts), are not excluded from the NFA. That is why the replicas have barrels over 16 inches in length.
• Serial numbers - Serial numbers of the Chinese/Navy Arms conversions are, so far as I've seen, always over 1100. Original Mauser carbines all have lower serial numbers. Original Mauser serial numbers are almost always on the left side of the frame, just above the stock attachment dovetail, and on the stock attachment iron just below the frame serial number.
The photo above is of a reproduction, but at least the serial numbers are in the right places.
• Pistol features - A number of features are common on original Mauser pistols, but rarely or never seen on original Mauser Carbines. Here's an example, a deactivated gun on the Arundel site -
Immediately apparent are the remnants of a MAUSER banner on the frame, the milled or grooved rails on the barrel extension, the lack of serial numbers on the left sides of the frame and stock iron, and (as we can tell from the shape of the ramp) the 1000 meter sight. As the description tells us only, Mauser C96 Carbine . This example has been refinished at some stage in it [sic] life (note, nothing about "repro" or "replica"), the verdict is - fake.
There are other problems with that specimen, such as the forearm wood, which should extend further down the front of the magazine, and end just above the floor plate. And there are probably some other problems I haven't noticed. But enough clues are visible to determine that it's not a real Mauser-made Carbine at all.