spas 12s are preban and arent really destructive devices, the spas15 however is.Destructive Devices: [Include] shotguns with a bore of more than .5 inch in diameter which are not generally recognized as particularly suitable for sporting purposes.” Examples deemed destructive devices by the ATF are the Street Sweeper, SPAS-12 and others. These guns are illegal to own unless they were registered during the ATF’s now-expired grace period.
With this in mind you might consider a Benelli M-4 entry gun or a Tromix Sagia