By that logic - there has been no call-up of militia.
You don’t get called up to the militia. You get called forth from the militia. In joining the Army, you were, indeed, called forth from the militia and you answered that call. Your right to keep and bear arms was not contingent on there having been a call, nor on you answering a call. The right was guaranteed to you, because you have the individual and collective responsibility to secure the state.
no uniformity in your ‘militia’, regarding equipment training and supply does not represent a well regulated militia.
Don’t tell me. Tell Congress that you want to be subjected to additional regulation in your role as a militiaman. They seem to think that they have enough regulation on the militia already. You tell me what else you think you should be required to do. Not to secure your right to keep and bear arms: they are expressly prohibited from infringing in gun ownership. They can’t stop you from owning a gun, but they can compel you to participate in militia training, as you are a member of the militia.