Reading the mass.gov guidance, it doesn't explicitly list restrictions on type of ammo used for shotgun, but it does rule out buckshot for muzzleloaders.

Your best bet is to post this question in the pinned "legal questions" thread in r/MAguns and you'll get the correct answer.

Archery: Archery equipment may be used during all deer hunting seasons. All bows, (recurve, long, and compound) except permitted crossbows, must have a draw weight of at least 40 lbs at 28 inches or at peak draw. Crossbows may be used by certain permanently disabled persons by permit only. Arrows must have well-sharpened steel broadhead blades not less than 7/8 inches in width. Expanding broadheads and mechanical releases are permitted. Poisoned arrows, explosive tips, airbows and bows drawn by mechanical means are prohibited.

Shotgun: No larger than 10 gauge. May only be used during the shotgun deer season. Rifled barrel shotguns are legal.

Primitive fire arms: Shoulder-fired muzzleloaders .44 caliber to .775 caliber; barrel length 18 inches or more with only one barrel operational. Inline ignition systems are permitted providing the firearm loads from the muzzle. Single projectile only (no buckshot). Sabot rounds, 209 primers, break/hinge-action muzzleloaders, and scopes are permitted. Powder limited to black powder or black powder substitutes. A muzzleloader is considered unloaded when cap or pan powder is removed.

Prohibited: Possession or use of rifles and handguns in any woodland or field, or use on any game during the shotgun deer season, including the Youth Deer Hunt Day.