20×149

20x149 is a designation for a type of ammunition. The "20" refers to the caliber of the projectile, indicating it is 20 millimeters in diameter. The "149" refers to the length of the cartridge case in millimeters. This ammunition is typically used in aircraft cannons, particularly those found on Soviet and Russian-designed aircraft.

The 20x149 ammunition is known for its relatively high muzzle velocity and destructive power, making it effective against ground targets and other aircraft. Common types of rounds include high-explosive incendiary (HEI) and armor-piercing incendiary (API) projectiles. These rounds are designed to detonate on impact or penetrate armor before igniting.

The primary weapon associated with the 20x149 round is the Nudelman-Rikhter NR-30 autocannon. This cannon was widely used in Soviet-era fighter jets, including variants of the MiG series and Sukhoi series aircraft, during the Cold War and beyond. The NR-30's high rate of fire and the effectiveness of the 20x149 ammunition contributed to its reputation as a formidable armament. While newer aircraft often employ different calibers and weapon systems, the 20x149 remains a significant part of military aviation history.