I'll just give you part of a quote from R. v. Généreux.
In 1992, Chief Justice Lamer said:
To maintain the Armed Forces in a state of readiness, the military must be in the position to enforce internal discipline effectively and efficiently. Breaches of military discipline must be dealt with speedily and, frequently, punished more severely than would be the case if a civilian engaged in such conduct. As a result, the military has its own Code of Service Discipline to allow it to meet its particular disciplinary needs. That Code of Service Discipline incorporates the Criminal Code offences that we talked about. Do you think it would be possible to insulate the activities of the military tribunals in the summary conviction trials from the Criminal Records Act? Do you think that's legally possible?