If my memory serves me correctly :

22 cal. or smaller rimfire or shotgun #2 or smaller.


Hopfully you will get an official reply from Encon.

Copied from the 2010 Hunting guide:

"# Rifles and Handguns- Rifles or handguns using ammunition larger than .22 caliber rimfire long rifle cartridges are prohibited on state-owned land. Rifles or handguns of any caliber are prohibited on State-leased and Permit-Required Hunting Areas (see Permit-Required and State-Leased Hunting Area sections for exceptions). The use of rifles or handguns to hunt turkeys, waterfowl, or any other federally regulated migratory game bird (except crows) is prohibited. The use of handguns to hunt deer is prohibited. Hunting on private land with ammunition larger than .22 caliber rimfire long rifle during the private land shotgun/rifle deer season is prohibited unless the user has a valid private land deer season permit and landowner consent form. The use of rifles to hunt deer is subject to additional restrictions (see Private Land Shotgun/Rifle Season). The use of ammunition larger than .22 caliber rimfire long rifle to hunt raccoon or opossum at night is prohibited. A person using a handgun for hunting must possess any required state/town permits to carry. Note that it is legal to use .17 caliber rimfire firearms in all situations where it is legal to use .22 caliber rimfire long rifle firearms.
# Shotguns - The possession of shotgun ammunition larger or heavier than #2 shot is prohibited on state-owned lands, state-leased lands, and Permit-Required Hunting Areas,at all times, and is prohibited on private lands during the Private Land Shotgun/Rifle Deer Season (see Permit-Required and State-Leased Hunting Area sections for exceptions). However, on any lands, waterfowlers hunting from a boat, blind, or stationary position may use up to and including size BB steel shot. The possession of lead shot while hunting waterfowl is prohibited. The use of shotguns larger than 10-gauge for hunting waterfowl is prohibited. Shotguns must not be capable of holding more than 3 shells when hunting waterfowl, other migratory birds (except crows), deer, and turkey. The use of shotguns to hunt deer or turkey is subject to additional restrictions (see Deer Hunting and Turkey Hunting). "