Heviarti, the gun registration memo you refer to was withdrawn, and never acted upon. Even when the commander put it out, it only applied to one company out of several thousand in the Army, let alone the entire military. It was issued to 110 Soldiers out of an army of approximately 1.5 million (not including National Guard and Reservists). That means that .000007 percent of Active Duty US Army personnel that were ordered to register their weapons before the order was promptly rescinded.
Just wanted to clarify that since you posted it without any context and with a sinister hint of suggestion that there is a pervasive anti-gun attitude among military personnel and their commanders. If that was your aim, you found one example, which is now defunct, that was hardly representative of the military as a whole to begin with. If that was not your aim, I'd be curious to hear what it is you are getting at.