Selling new never used AR15 M4 style big bore upper receiver for $79 (reg $160)...


Ejection port opening is .665″ wide for use with 458 SOCOM, 375 SOCOM, 450 Bushmaster, 12.7×42 etc, but can also be used for smaller calibers such as .223/5.56...


Includes charging handle & engraved dust cover...


Caliber: Multi 


Weight: 8.5oz


Material: 6061 Aluminum


Brand: Tromix