Cold hammer-forged barrel - Longer-lasting.
Piston-driven action - Much cleaner system. After 30 rounds fired on full automatic the bolt can be handled by the bare hand. 
Free-floating fore-end - Can be removed to clean or alter the gun and reassembled in minutes.
New iron sight design.
Comes in four variants (different barrel lengths):
- D10RS (10" barrel)
- D145RS (14.5" barrel)
- D165RS (16.5" barrel)
- D20RS (20" barrel)
Environmental survivability - Can be fired immediately after being submerged in water or buried in sand,  and testing by Heckler & Koch shows it can also be fired after being buried in mud.