https://www.sigsauer.com/store/sig5...embly-14-5-in-semi-special-configuration.html
SIG516 Gen 2 Upper Complete Receiver Assembly, 14.5 in, Semi, Special Configuration
The SIG516 14" upper allow operators to upgrade their current AR-15/M16/M4-type rifles from direct gas impingement systems to the SIG SAUER advanced short-stroke pushrod system. This advanced operating system reduces carbon fouling, excessive heat and unburned powder in the action, ensuring reliability and function that is unmatched. A standard 5.56mm NATO chrome-lined chamber and bore ensure reliable function in any environment. Barrels feature an A2 flash suppressor and are threaded 1/2 x 28 TPI, allowing the SIG516 to adapt to a number of aftermarket accessories and suppressor mounts.
SIG516 Gen 2 Upper Complete Receiver Assembly, 14.5 in, Semi, Special Configuration
The SIG516 14" upper allow operators to upgrade their current AR-15/M16/M4-type rifles from direct gas impingement systems to the SIG SAUER advanced short-stroke pushrod system. This advanced operating system reduces carbon fouling, excessive heat and unburned powder in the action, ensuring reliability and function that is unmatched. A standard 5.56mm NATO chrome-lined chamber and bore ensure reliable function in any environment. Barrels feature an A2 flash suppressor and are threaded 1/2 x 28 TPI, allowing the SIG516 to adapt to a number of aftermarket accessories and suppressor mounts.