Hm...I don't know anything about shotguns really, but am bored, so I'm searching
www.google.com for stuff. Here are some choice bits of information:
Guns Magazine, Jan.2000: 'Goose gunners like Long Tom autoloaders chambering 3 1/2" 12 or 10 gauge magnum shells.'
(I guess 'Long Tom' is nowadays used for long-barrelled shotguns in general?
)
From another site:
"Long Tom" was a trade name used by the J. Stevens Arms Company and was also a Sears Roebuck brand name for single barrel shotguns as long as thirty-six inches. Sears used the name on many models over a lengthly period.
From someone at Gun Parts Inc.:
Long Tom is a trade name used on guns sold by Sears Roebuck & Co.
Hope this helps.