The Gas regulator could be softened by heat BEFORE reaming any of the gas ports. With modern metals, it might be possible to use a carbide drill to open the ports out as an option? As mentioned by Peter, & myself in my original post. The gas port in the barrel SHOULD be of sufficient size in it's present state before needing to touch that. It is the GAS REGULATOR you should tackle first. Though to reiterate what Peter has explained. The Reg's ARE very hard! But I look at it from this viewpoint. They Were drilled/machined originally. WHY therefore, can they not be modified today?.........I would go the heating up & letting down route in the first instance to soften the metal. Before attempting to ream/drill any of the gas ports in the regulator. (Don't forget to push out & remove, the retaining cross pin/spring at the rear of the regulator. BEFORE applying heat to it!!!)