The Astra modelo 400 was a Spanish service pistol produced by weapons manufacturer Astra-Unceta y Cia SA[2] as a replacement for the Campo-Giro 1913/1916, which had also been chambered in 9mm Largo.
The 400 was considered heavy as in order to handle the power of the 9mm Largo round in a blowback action the 400 had a reinforced slide and tough spring.
The Spanish War Ministry of King Alfonso XIII began tests in 1919 to replace the Campo Giro pistol as the standard military sidearm.
Astra pistols were supplied to Republican Spain and to the Basque government which controlled the plant until the Bombing of Guernica in April, 1937.
Astra continued private production until 1950 even though in 1946 the Spanish military adopted the Star Model A as the standard sidearm.
[4] The Astra 400 is heavy compared to many contemporary service pistols of the time like the Tokarev TT-33 but is similar in weight and length to the Colt 1911.