I just purchased a M-4 Super 90 M1014 ($1500) the model i has a engraved American flag on the right side of the receiver. My understanding that this is a collectible one to have if you can find one. Also I purchased a 2rd tube extender from Daves Metal Works I must say great quality and fast shipping. Upon installing the new part I was wondering why the tube only holds 6rd (2 3/4 rounds) in the tube, there is no tube limiter being used. Any help will be definitely appreciated thanks for the help.