Minnesota, USA slingshot laws

Slingshots are 100% legal in the state of Minnesota, even with arm-braces. The only places I've found that prohibit slingshots are the City of Duluth and State Parks.

Hunting small game via slingshot is also legal in Minnesota, as long as trespassing, licensing, season, and bag limit regulations are followed. The is no season restriction, bag limit, or license required for pigeons or red squirrels in Minnesota.

Sources:
City of Duluth
http://www.duluthmn.gov/clerk/council/resord03/03-058-o.htm
Sec. 49-2. Manufacture, possession, etc., of slingshots, air guns, etc.
No person shall manufacture, sell, dispose of, use or have in possession any slingshot within the city, unless the person so desiring to manufacture, sell, dispose of, use or have in possession any slingshot has first applied to and received from the chief of police a permit for such purpose.
The word, slingshot, as used in this Section, shall be considered to include any instrumentality or device to which there is attached directly or indirectly, a rubber band or any other elastic, which instrumentality or device is capable of being used or employed in shooting or propelling a bullet, shot, stone or other hard missile.

Minnesota State Parks:
http://files.dnr.state.mn.us/maps/state_parks/spk00142.pdf
The use of firearms, explosives, air guns, slingshots, traps, seines, nets, bows and arrows, and all other weapons is prohibited in state parks.

http://www.dnr.state.mn.us/state_parks/rules.html#hunting
Hunting is prohibited in Minnesota state parks unless authorized by the Commissioner of the Department of Natural Resources. Learn about special hunts held in state parks.

Hunting in Minnesota
http://www.dnr.state.mn.us/regulations/hunting/index.html
(Also confirmed slingshots are a legal small game weapon with a Minnesota Conservation Officer/game warden)