Skip to main content

.338 Thunder


The .338 Thunder is a rifle cartridge based on the .308 Winchester case necked up to take .338 caliber projectiles. It was created by AMJ Precision in 2022 and intended as a special purpose big bore cartridge with reasonable recoil for lightweight self loading rifles. Unlike most necked up calibers of its kind it only sacrifices a single round of capacity in a standard 20 round magazine, providing 19 rounds of .338 Caliber ammunition in an AR-10 Platform.


Note: 343.2 m/s is the subsonic barrier - anything below that is considered subsonic. Subsonic ammunition removes the bullet crack down range making the round better suited to stealth.

Ammunition Type Damage Bullet Velocity (m/s) Barrier Penetration
Ball 19.55 780  
Match 23 580 0.6
Subsonic 53.25 120 2
Armor Piercing 41 465 19.4
AP Reactive 33 + 1 597 15.9
AP Incendiary 36 + 2  470 12.3

Note: Barrier penetration represents the rounds ability to go through walls and barriers. Armor piercing represents the rounds ability to penetrate body armor plates.