I have been running a 7.5" upper in 5.56 for a few years now and although it is a lot of fun, 5.56 out of such a short barrel is pretty useless ballistically. I decided to turn it into a useful PDW by building a 6.8 SPC upper. Picked up an Vltor VIS stripped upper locally and ordered a Noveske Diplomat 6.8 SPC barrel and KX3 muzzle device. I decided since it would be a true PDW back-up iron sights for distance were not needed but an optic good up to at least 100 yards or so without a battery source is. The Trijicon RX30 is perfect as the lense is gigantic, the dot is clear and crisp in all light conditions and it does not have the washout problem that the old Reflex II’s did. Even when running in total darkness with just the light from the TLR1 the dot is highly visible. It is a totally bombproof optic and I doubt it will every go down. I have been using it so far for indoor 2-gun matches and it rocks.
MadDog 
