Take a quick look at this CNET summary of Real ID and its implications on things like travel, border crossings and entering federal buildings. Yet since handgun purchases (from a retail location) generally require a federal background check, Real ID has implications there too. From the article:
Q: What about buying firearms?
That's an open question. Homeland Security last month refused to rule out requiring Real ID for firearm purchases in the future.
When asked about requiring Real ID to buy a firearm, Homeland Security replied: "DHS will continue to consider additional ways in which a Real ID license can or should be used and will implement any changes to the definition of 'official purpose' or determinations regarding additional uses for Real ID consistent with applicable laws and regulatory requirements. DHS does not agree that it must seek the approval of Congress as a prerequisite to changing the definition in the future."
So there you have it. Another intervention is looming.