“The original BA Hanson profile barrels have a .750” diameter at the gas block journal and it is more of a light/medium contour. The BA Hanson .625” barrels are called this due to .625″ diameter at the gas block journal. This profile is a thinner and lighter weight version of the original BA Hanson profile. Each BA Hanson barrel comes with a pinned, lo-pro Gas Block already installed which makes them an excellent value.”