Word of caution when you have your barrel out. The #1 way people break their barrel clamps is that they don't notice the dust cover pin has moved forward and tighten the clamp over the end of the pin. That pin is captured by the clamp and can slide forward when the barrel is off.
Also a note on the NGSW bids. Reportedly Textron has withdrawn and I can't see the US Mil ever going w/ a bullpup. Might leave only one standing.