Hi all - just a quick question. What makes a bb gun a firearm as opposed to a rif? I'm talking about 4.5mm bb compared to 6mm bb guns, the latter used more in airsoft.

Take one of the favourite bb guns that are about - the Tanfoglio Witness 4.5mm - what makes this a firearm and what makes, say, the Tokyo Marui 6mm a rif?

Is there a minimum power requirement that makes a bb firearm a, well, firearm instead of a rif and if so, what is that power?

Cheers all