The Astra modelo 400 was a Spanish service pistol produced by weapons manufacturer Astra-Unceta y Cia SA. as a replacement for the Campo-Giro 1913/1916, which had also been chambered in 9mm Largo. It was the standard issue sidearm in the Spanish Army during the Spanish Civil War and also saw service in Germany during World War II.
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. The Astra 400 was designed to be safe to fire with a simple blowback action unaided by any breech-locking devices. This is only possible with a heavy slide and strong recoil spring. It was fitted with an internal hammer which was considered very hard to c0ck. The pistol also featured grooved finger grips and left sided trigger catch behind the trigger guard. The original design was chambered in 9mm Largo, but later variants would be chambered differently to better fulfill different military needs.