The claim that the Founders would have demanded that Congress take action is absurd, and wouldn't be made by anyone honest who is familiar with our founding history. If they would have felt a need to regular guns at some level, they would have believed that was the province of states/localities.
Prior to the passage of the 14th Amendment, there was no legitimate argument that the Constitution limited the power of states to regulate firearm possession.
People sometimes forget - or more likely never understood in the first place - that the Constitution and Bill of Rights in general limited only the power of the federal government, not that of the states. States were free to regulate religion, speech, etc..