Model 1900



The first auto loading version of the Mondragon rifle.   This one is marked “Modelo No. #3″  “1900”,  a carbine in 7 x 57mm Mauser

In the picture below, you can see the lineage from the manual bolt action rifle to the auto-loading version. The upper gun is an early 1890’s model straight pull carbine. The lower gun is the Model 1900 semi-auto carbine.


The Model 1900 utilizes gas tapped from the muzzle end of the barrel to drive a piston to which the bolt is attached (see Gas System for details) and cycles with the aid of a return spring. This system is the logical progression from his 1890 straight pull bolt action rifle. All semi-automatic guns are basically a modified straight pull action. Just add high-pressure gas or recoil to move the bolt back and a return spring to drive the bolt forward and reload.

An interesting design feature of the Model 1900 is this cam system (below) used for charging the weapon. Pull back the charging handle, and this cam lets go of the return spring making it very easy to reload. Once the weapon is fired, reloading is automatic. In weapons of today, one must overcome the return spring to reload.   In the later Mondragon models (FSK15) the auto disconnect feature was removed and a manual bypass was provided for…pity because the original looks cleaner.


The fact that there is no serial number and the markings on this gun are “Modelo No. 3” Model 1900 and the solid bolt handle which is only seen on the first designs.

This gun says “prototype” to me.

Original Patent

Many of The Mondragon rifles have all been linked to this patent drawing, this patent drawing is for the Model 1900 only.  Only 2 patents were taken out, one for the manual reloader Model 1890 and one for the semi-automatic Model 1900.

In 1903, the Model 1900 was tested by the British army, along with rifles of other nations. The result was to be a classic case of pushing an immature design for sale before the bugs are worked out.  Improper heat treating of firing pins and the extractor caused failures after about 5,000 rounds. The ammunition supplied for the demonstration was not made to specs and caused failure to feed malfunctions in the autoloading mode. The large opening on the RH side, where the bolt travels, allowed sand and dirt into the feed mechanism. NOTE# The large hole for ejection exposes the internals, where the bolt travels for cartridge ejection and reloading this has been a problem for all semiautomatic rifles. With the exception of the exposed bolt race and magazine, the other issues were remedied in the Model 1908 (see Model 1908 section).

note# A recent article in Firearms News featured a 10,000-round showdown between the M16 and AK47 designs, and both guns had failures after about 5,000 rounds.

Other Prototypes Based on the Model 1900


Photos courtesy of Royal Military College of Canada Museum/Museé Du Collége Royal Du Canada.

My Observation: Does this magazine look like it should be for a rimmed cartridge?

Specification Sheet for the Model 1900

Country of Design: Mexico
Designer: Manuel Mondragon


  • Calibers: 30-30 Winchester, 6.5 Mondragon, 7.65 x 54mm Argentine and 7x57mm Mauser
    (The 30-30 was a one-time chambering presentation piece for President Diaz, the 7.65 cartridge rifle was specifically designed for the Argentine Army)
  • Type of reloading mechanism: Semi-automatic, Gas operated
  • Magazine capacity: 6, 8 or 10 rounds, depending on caliber

An 8 round en-bloc clip was used for reloading.   The disadvantages of the en-bloc clip must have been discovered early on because this is the last Mondragon designed gun to utilize this method.   The Model 1908 and subsequent used either stripper clips or a removable magazine.


  • Quantity: Approximately 200
  • Years made: Late 1890 – 1900
  • Manufacturer: Swiss Industrial Company (SIG), Neuhausen, Switzerland
  • Entered service: Only a Trials gun or proof of concept


  • Weight: 7lbs 12 oz
  • Barrel length: 21.5 inches
  • Total length:  42 inches
  • Sights: No graduation on long-range sight, battle sight is probably 400
  • Serial Number Range: 1-200 (if any)

NOTE:  Some of the Model 1900 rifles appear to have repetitive serial numbers.  A new set of serial numbers appears to have been assigned for each caliber.    It is possible to see two serial #3’s – one in 7 x 57mm Mauser and one in 7.65 x 54mm Argentine, as an example.

Patent Information

US Patent Applied for on: August 8, 1904
US Patent (#853,715) granted on: May 14, 1907

The Model 1908 falls under the basic patent of the Model 1900 “with improvements”

Known examples…………………………………………………………………………………………5

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