It's a matter of federal law, applicable to all states. For a rifle, it must be at least 16 inches. For a shotgun, 18 inches. Anything less requires an NFA Class II permit for a short-barreled rifle or shotgun.
No
30 inches. A longer barrel gives you better accuracy.
16 inches, as required by the NFA.
See A(6) here http://www.atf.gov/firearms/faq/faq2.htm#a6
Federal law is 18
Should be marked on the barrel
Check the receiver and barrel.
50-500 usd
Single barrel, over/under, side by side, semi-auto, pump, lever, full-auto
Have a Model M-846 (Montgomery Ward) semi auto with 18 inch barrel.
Single barrel, over/under, side by side, semi-auto, pump, lever, full-auto
Model 24 is a semi-auto 22.