Hammer forged, chrome lined. All you need to know.
Well, not exactly - they are hammer forged, they are chrome lined and they're a pretty good quality "run of the mill" GI type barrel. They don't use a different barrel for military sales - in other words, you're getting a machine gun barrel that is very durable, and the metallurgy is pretty darned impressive for what you pay. You're not going to get the quality of production you'd get from the other CHF/CL barrel out there, but you're not paying for a Colt Canada barrel.