While noted that Gyrojet Rocket Carbines saw limited production, the experimental Gyrojet Carbines were almost unheard of. This is one of the few in the world. The United States National Firearms Museum is keeper of the experimental pistol A0029. This is experimental carbine A0028!!! What makes this even more unique is that is still has it's original factory leather sling!

Another bit of information, MBA in their experimental stages had made both their pistols and rifles serial numbered one after another. They did not make one of each with the same number.