The ballistic mechandrite a tech-priest only sacred implant seems under powered in comparisson to the weapon miu available for everyone.
simple comparrison
ballistic mechandrite = compact laspistol. Weapon MIU can have a choice of guns mounted
ballistic mechandrite = reaction. Weapon MIU = free action.
Yes the mechandrite is 2m long but has no optical targetting so it can't be too far from the tech priests "eyes". I can see a possible tactical advantage paired with either a servo-skull or optical mechandrite for shooting round corners but I would think that the equipment they make for themselves would be on a par with that they sell.
Should fring this mechandrite be a free action, like the MIU, while you are firing it in the same manner as a normal pistol and a reaction to move it to a new position? Thoughts comments and criticisms welcome even if you think I'm completely off track