Put the first 1000rds thru my S1 Carbine yesterday, and it was nothing less than the perfection I expected (and that I am used to with my PS1)... Dialed in the BUIS, then the Aimpoint Pro for the RDS optic at 50 meters, and accuracy was very good out to 150 meters... what an awesome weapon system and a pleasure to shoot. Also, just an off-hand fyi that the new MagPul D-60 drum when inserted does not allow the stock to completely fold... it hits the drum body before reaching its detent at the full-folded position...