Made in the USA, by CMMG, this premium barrel is highly reccommend for any SBR or pistol build. 
 
The USAF recently adopted the 12.5" barrel for use in the GAU-5A ejection seat rifle weapons system based on the requirement to reliably hit a man sized target at 200 yards. A 12.5" barrel will give a slight muzzle velocity increase over the 10.5" barrel as well as improving accuracy.
The barrel has a salt nitride bath finish which provides a two-fold increase in the hardness of steel. An advantage of salt nitride bath over chrome lining is the greatly improved corrosion resistance both on inside and outside of the barrel (chrome lining offers no outside protection), paired with a reduced cost in manufacturing.