HK 416 Vs M4 w/ DD Block II

[JoKeR1147]

Which type of gun is more accurate for milsim? I'm specifically going for a cag/ace loadout but I hope to make the loadout so tha with a few tweaks it could double up as a SFG or ODA loadout. Which gun would better fullfil these roles? I heard they are phasing out the block II m4s but that seems unlikely to me given how many operators voiced a preferance for the m4/m4a1 patform over the hk 416 platform. Anyways, and assistance is appreciated, thanks in advance.