I can't really cite a source, but I have read in several places that blank firing guns (ONLY able to fire specially made blank cartridges) are not firearms, and are not regulated by the ATF. Stands to reason at that point that full auto or semi means little.
"If you carry a gun, people will call you paranoid. That's ridiculous. If I have a gun, what in the hell do I have to be paranoid for." - Clint Smith