J6 was a crime against the federal government on government property in the District of Columbia.

The feds do have this felony murder law, but it seems to be narrower in scope than many state laws. For instance, the case where law enforcement shoots a perp did happen at the capitol, but it seems like it can’t be charged as felony murder under the federal version of the law.

Also, the federal law lists specific crimes only that can be used as underlying felonies, and I suspect that “obstructing an official proceeding” and even “insurrection” are not specifically on that list. Possibly, the feds would have had to charge and convict on simple burglary to apply felony murder.

I don’t think any felony murders were actually charged. And a great many J6 defendants were charged with no felonies at all, so they would not be eligible.