I could be wrong, but I read that to mean "While the rifles produced were both reliable and accurate, it quickly became clear that the complexity of performing the conversions required factory work, rendering the plan for mass unit-level conversions completely unfeasible and dooming the project to cancellation."
But you're right, as written it's kinda funny.
I hasten to add that my interpretation is a guess, as I've never even seen one of theese club or military conversions.