There are real problems in producing semi auto only variants of these guns. They are complicated, and have many complex parts which were made by conventional machining processes, often from forgings. Parts kits from decommissioned guns are the only economic source of most of the parts. The receiver, and fire control group, as well as the bolt will have to be new production. A design that cannot be readily converted to full auto must be developed. There must be a lot of reverse engineering to marry the old and the new. In all likelihood, the design will have to be hammer or striker fired from a closed bolt; no regulation requires this, but open bolt designs are often too easy to alter for auto fire. Some original parts will have to be altered. The receiver would likely have to be CNC machined from a billet. Have a really good look at a BREN, etc., receiver, and look at the number of different profiles which must be machined. The Browning guns are probably the easiest to remanufacture: closed bolt to start with, and a rivetted box receiver, rather than one machined from a solid chunk. The Bren receiver blank weighed more than the finished gun.
OK, the gun is not going to be cheap. Then, what is the market for the gun? How many are you going to sell in this country? Enough to justify economic production? Look at the price of the AIA Lee Enfieldish rifles. They are a piece of cake to manufacture compared to a version of one of the old classic MGs.
Though sadly they would be 5 round limited unlike the belt fed stuff.
