In the 1920s, Hotchkiss developed a range of anti-aircraft automatic weapons in the 13.2, 25 and 37 mm calibers. They were all based on the same type of
gas-operated action, similar to the one used in the 8 mm
Hotchkiss Mle 1914 machine gun, which had proven extremely reliable during
World War I and was still in service. The 13.2 mm machine gun project was started in 1922 as an aircraft machine gun, but the French government classified the belt-fed version (while not funding its further development), and only the magazine version (only useful for ground and naval use) was allowed to be exported, starting from around 1927.
Performance The Hotchkiss M1929 machine gun had a
cyclic rate of fire of 450 rounds per minute, but their practical sustained rate of fire was just 200-250 rounds per minute due to limited magazine capacity. The majority of Hotchkiss M1929 machine guns were fed by overhead, 30 round, curved
box magazines. These magazines would run empty in 4 seconds, requiring frequent magazine changes which limited their rate of fire.
Cartridges The Hotchkiss M1929 machine gun was initially chambered for the cartridge
13.2 × 99 mm Hotchkiss "Long", which essentially was a
12.7 × 99 mm Browning (
.50 BMG) cartridge necked up to 13.2 mm
caliber. This cartridge however proved to wear out gun barrels too quickly and to alleviate this inconvenience Hotchkiss introduced a new cartridge for the M1929 machine gun in 1935, featuring a slightly shorter cartridge case and reworked projectile shape, becoming the cartridge
13.2 x 96 mm Hotchkiss "Short". The new cartridge was practically identical to the original 13.2 x 99 mm cartridge except for the length of the neck, reducing the full case length to 96 mm. This minimal change was done so that existing weapons and the production line did not require any modification to fire the new cartridge, but was sufficient to fix the barrel wear issue.
Configurations The Hotchkiss M1929 machine gun came in a number of different configurations depending on their intended role. There were single, double and quadruple barreled
anti-aircraft weapons on a high-angle pedestal and tripod mounts, as well as low-angle bipod mounts for
anti-tank and
heavy machine gun roles. French infantry commanders, who had expressed interest in acquiring light anti-aircraft guns, refused to accept the 13.2 mm. They argued that the heavy bullets falling down could be dangerous to friendly troops, and preferred larger calibers for which self-destructing shells were available. But the 13.2 mm Hotchkiss saw extensive use as a naval gun and was also chosen by the French cavalry for some of its armored vehicles. File:Machine gun (AM 775502).jpg|A Japanese 30 round box magazine File:Three different 13.2 mm cartridges (rotated 90).JPG|13.2 mm cartridges top to bottom:
13.2×99mm Hotchkiss Long13.2×96mm Hotchkiss Short
13.2×92mmSR Mauser TuF File:Machinegun carriage Le Prieur patent.jpg|A quadruple naval mounting, as illustrated in US Patent 1700902 filed by
Yves Le Prieur == Service ==