-5.56 Echo line rifle 

-350 Legend upper receiver without a BCG and charging handle

-5.56 and 350 Legend magazines 

 Simply swap the BCG and charging handle over from the 5.56 to the 350 legend and you are ready to go! 

Echo 3 Ordnance 350 Legend barrels were designed utilizing dimensions for Winchester 350 Legend ammunition. We highly recommend only using Winchester brand 350 Legend FMJ and Power Point ammo, as other brand's cartridge dimensions may vary.