It’s no secret that the U.S. military holds some of the most powerful firearms ever. Specifically, the U.S. Military houses three of the deadliest sniper rifles: the Barrett M82, M40, and the Barrett MRAD. The Barrett M82 is known for the massive cartridge it fires, the .50 BMG, giving it an unrivaled stopping power and lethality. On the other hand, the M40 has a 7.62×51 mm NATO cartridge and is considered one of the most popular sports and hunting rifles. Finally, the Barrett MRAD offers a unique precision shooting platform and is exceptionally modular.
Source: https://nationalinterest.org/blog/buzz/youre-so-dead-3-deadliest-sniper-rifles-us-military-181388