REMINGTON 300 WIN MAG AMMO FUNDAMENTALS EXPLAINED

I want to locate a barrel that's for your wingmaster only? What length can get me to original and so are there longer barrels offered? To who should I change Moreover ebay?KC but upside down it claims CK. not even stamped all of that well. In terms of the rest of the serial on the opposite , its S656868V. Far more good quality from the wingmaster.