In my experience, MGM has a slight accuracy edge over factory T/C barrels. The two factory barrels I shot at 100 yards (243 Win and 300 Win Mag) were about 1.5 MOA capable with the handloads I used, although in more experienced hands, they might do a bit better. My two revolver-cartridge MGM barrels (460 S&W and 327 Federal) were about 1.25 MOA with factory ammo and closer to 1 MOA with handloads. My 221 Fireball barrel regularly shoots sub-MOA.