This question came up in early June (last post on 6/4). A link to that discussion is http://www.huntingnet.com/forum/tm.aspx?m=2147347&mpage=1&key=&#214734 7. A list of some of the approved cartridges can be found at (http://www.in.gov/dnr/fishwild/about/rules.html). The list is :
The rifle must fire a cartridge that meets the following specifications:
A) fire a bullet of three hundred fifty-seven thousandths of an inch (.357) diameter or larger; (B) have a minimum case length of one and sixteen hundredths (1.16) inches; and (C) have a maximum case length of one and six hundred twenty-five thousandths (1.625) inches.
Some cartridges that will be legal include the following:
.357 Magnum
.38-40 Winchester
.41 Magnum
.41 Special
.44 Magnum
.44 Special
.44-.40 Winchester
.45 Colt
.454 Casull
.480 Ruger
.475 Linebaugh
.50 Action Express
.500 S&W


My overall suggestion was to get an 1894 Marlin in 44 Magnum. Due to the quick handling, relatively short 20inch barrel and a quick follow up shot I use for one of “brush gun”. I have no scope on it, but one would be very easy to put on. Other notable options seemed to be the H&R single shot in .500 S&W or 44 Magnum.