You’d have the right to keep, bear, and use arms in self-defense whether there was a Second Amendment or the US Constitution or not. From Laurence Vance at lewrockwell.com:
On January 4, 2020, on just the second day of the 117th Congress, Representative Sheila Jackson Lee (D-TX), introduced the Sabika Sheikh Firearm Licensing and Registration Act (H.R.127) “to provide for the licensing of firearm and ammunition possession and the registration of firearms, and to prohibit the possession of certain ammunition.” The bill is named after a Pakistani Muslim exchange student who was shot to death in a Santa Fe, Texas, high school in 2018, although seven other students and two teachers were murdered as well.
So far the bill has no cosponsors. That’s a good thing because this is one of the most evil bills ever introduced in Congress (and members of Congress have introduced some utterly evil bills over the years).
Under this bill, “the Attorney General, through the Bureau of Alcohol, Tobacco, Firearms and Explosives, shall establish a system for licensing the possession of firearms or ammunition in the United States, and for the registration with the Bureau of each firearm present in the United States.”