anyway fixed this by using a ball and socket styled joint that looks like a pokeball.
anyway heres the picture of the arms new features. il explain them below the picture.

shot 1: iv kept the human fingers as id like the mec to be able to hold guns. but iv concealed them abit.
shot 2: shows the two new melee class weapons iv added.
shot 3: shows the blades that retract and the arm, for general melee, close quarters damage.
shot 4: a break shunt. used to clear rubble, sprize open blast doors ect.
i think it looks alot better than the previous. iv almost completed the mec project now. a few more days and it'l be finished.