The following information on the Model 1890 Spanish Mauser comes from Chapter 18 of Mauser Rifles and Pistols by W. H. B. Smith. Mauser Rifles and Pistols is also available to purchase in print.
According to the records of Ludwig Loewe & Company the prime manufacturers, Spain adopted in 1890 a slightly altered Turkish pattern rifle. This rifle also has the box magazine projecting below the stock.
In 1892, 1893, and 1896, minor modifications in design were adopted by Spain. The only major change was the magazine which was made flush with the bottom of the stock, and was staggered.
These Mausers differ from the Belgian already described only in the following general details:
1. Caliber. The Spanish caliber is 7mm or .276 inch. (Modern “7mm Mauser” commercial ammunition can be used).
The cartridge is rimless and measures 3.08 inches overall and weighs 377.4 grains. The bullet is round-nosed and made of lead with a steel jacket. The bullet length is 1.21 inches, the maximum diameter is .284 inch, and the bullet weight is 172.8 grains. The charge is 38.3 grains of nitro-cellulose. The muzzle velocity is approximately 2290 feet per second and the chamber pressure about 45,000 pounds per square inch. (Modern specifications vary somewhat).
2. The Spanish pattern as used in 1892 is practically identical with the Boer rifle of the same year which uses the same cartridge.
3. Barrel is polished and browned on the outside and is turned down in steps with the portions between tapering. Sights are attached to barrel.
4. Rear sight has a thin tube underneath which encircles barrel and is screwed and soldered to it. The right angle to the leaf is graduated for 400 feet. The face of the leaf itself is graduated from 400 to 2000 meters.
5. A half length rod for cleaning is provided. One end is screwed into a notch in the stock and the other end is provided with a slot for the cleaning rag. The rod is intended to be joined with others to form a common rod for several soldiers.
6. All other differences from the Belgian are the same as those already given for the Turkish rifle.
The carbine of this pattern is the same as the rifle with minor differences as follows:
The rear sight leaf is graduated from 400 to only 1400 meters. Bolt lever instead of projecting in straight line is turned down to lie close to the stock.
Barrel projects 1/16 of an inch through the nose cap. The nose cap is extended upwards at its sides to form wings to protect the front sight. It is not equipped to receive a bayonet.
The lower band has a sling swivel on the right hand side. The rear attachment point for the sling is a plate below the rear of the small of the stock. The ring for the band is attached to this plate.
The weight, length and barrel length are correspondingly shorter.
The forestock comes to the muzzle on the carbine.
The carbine weighs about 7.5 pounds and measures 37-inches overall.