Like the name "Colt", the distinction between Walther and Umarex is blurred when it comes to these .22s. Umarex appears to build them and import them. Over the last year however these Colts are stamped built by Walther and imported by Walter. My older Colt M4 Tactical .22 says built by Walther, imported by Umarex.
Whatever. At least it appears an airsoft company can make rimfires. These are nice .22s.
The biggest issue with assembling an AR isn't so much getting the parts together right - it's getting the right parts together.
US Army 1966-69, VFW Life Member, Retired Geek