Quote:
Note the deffinition is slightly different from that used in the rest of the GCA, as are all the definitions used in NFA.

That is what you are missing. The short bbl shotgun comes under control of the National Firearms Act, which went in effect in the 1930's, '32 I believe was stated.
Quote:
We treat any normal shotgun from 1898 or before as an antique evern though they shoot readily available shotshells like 12g.

These come under the jurisdiction of the 1968 Gun Control Act

Miller/TN
I Didn't Say Everything I Said, Yogi Berra