Here is the IC and a link to the case law. IC 35-47-1-6 (emphasis added) "Handgun"
Sec. 6. "Handgun" means any firearm:
(1) designed or adapted so as to be aimed and fired from one (1) hand, regardless of barrel length; or
(2) any firearm with:
(A) a barrel less than sixteen (16) inches in length; or
(B) an overall length of less than twenty-six (26) inches.