Despite coming out strongly for the .300 AAC BLK cartridge, Wilson Combat has developed their own 7.62x39mm-equivalent for the AR-15. The 7.62x40mm WT is a 5.56mm NATO cartridge necked up to .30 caliber. To convert an AR-15 to use the 7.62×40 WT a barrel change is (obviously) required and a special Wilson-modified version of Lancer’s L5 AWM polymer magazine.
The cartridge is designed with tactical/self-defense and hunting use with soft-point or hollow point projectiles. The company published this comparison with the 5.56mm NATO, 6.8mm SPC, 7.62x39mm & .300 BLK:
5.56 Nato (16” Barrel)
55 gr: 3150 FPS Muzzle Velocity and 1212 Foot Pounds of Energy
62 gr: 3000 FPS Muzzle Velocity and 1239 Foot Pounds of Energy
77 gr: 2750 FPS Muzzle Velocity and 1293 Foot Pounds of Energy
7.62×39 (16” Barrel)
123 gr: 2320 FPS Muzzle Velocity and 1470 Foot Pounds of Energy
6.8 SPC (16” Barrel)
110 gr: 2550 FPS Muzzle Velocity and 1594 Foot Pounds of Energy
300 BLACKOUT (16” Barrel)
125 gr: 2275 FPS Muzzle Velocity and 1436 Foot Pounds of Energy
Unlike the .300 BLK, the 7.62×40 WT has not been designed for suppressor use (ie. it is a supersonic cartridge). Remington will be manufacturing supersonic and subsonic BLK loads.
Wilson Combat 7.62×40 WT loaded with 110 gr. Sierra HP is on sale right now at a cost of $18 for 20 rounds at the Wilson Combat store.