These are the first public photos after the gun was presented at the "day of the infantry" in Hammelburg. The HK 121 is scheduled to replace the aging Rheinmetall MG3 for both mounted and dismounted use in the German Army.
Note the nifty drum mag ( or is it just a "belt-pouch"?) and the new scope by Zeiss / Hensoldt. The G36 will be updated with new 4 X 30 power scopes as well - those are however not battery-powered as the one in the pictures.
If you look very carefully you can spot the HK 417 - which is rumored to be fielded as the new Bundeswehr DMR G27.