1. During the "primitive firearms" (muzzleloader) part of the open deer season, muzzle-loading primitive firearms must be of a type similar to those in common use during the mid-1800s, and which meet the following criteria:

(a) loaded from the muzzle,
(b) fired from the shoulder,
(c) has either a caplock or flintlock ignition system. So-called "in-line" ignition systems which have a horizontal firing mechanism instead of a traditional hammer system are lawful, provided they meet all other provisions of these requirements;
(d) may be either rifled bore or smoothbore,
(e) is of a caliber not less than .44 nor greater than .775,
(f) has a barrel length of 18 inches or longer,
(g) is used only with black powder or a synthetic substance such as "Pyrodex" which is approved for competitive muzzle-loading shoots by the National Muzzle Loading Rifle Association,
(h) contains only one usable barrel; in the case of primitive firearms with double barrels, one barrel shall be made inoperative by removal of the nipple and hammer,
(i) is used with only a single lead projectile, including a round ball, pumpkin ball, Minie or Maxi bullet, or other spherical or conical projectile (i.e., no buckshot). Sabot rounds are lawful, regardless of composition, as are jacketed or belted projectiles,
(j) muzzle-loading firearms which use shotgun (209) primers are lawful, provided that the firearm meets all other provisions of these requirements;
(k) conventional sights, including telescopic sights, are lawful on muzzle-loading firearms; however, laser sights or any other sights which project a beam are unlawful.
(l) firearms with a break-open ("hinge action") breech are lawful.

2. Primitive firearms used during the "shotgun" part of the open deer season, or for the hunting of black bear or wild turkey, must meet the above criteria, except:

(a) firearms with a break-open ("hinge action") breech are lawful;
(b) firearms with more than one operable barrel are lawful; and
(c) for the hunting of wild turkey, must be smoothbore and may be used only with shot not larger than #4 nor smaller than #6,

3. All other muzzle-loading long guns of any type and design may be used during the regulated open season for other species, provided that only shoulder-fired smoothbore muzzleloaders may be used in those areas and at those times when hunting is restricted to shotguns. Shoulder-fired muzzleloaders with a rifled bore may be used when rifles are lawful for hunting, except when rifles are restricted to those not larger than .22 caliber long rifle. Muzzleloading shotguns greater than 10 gauge (.775 caliber) may not be used for hunting. Refer to the Plain Language summary for hunting with handguns for information concerning muzzleloading pistols.

4. Some modern-design muzzle-loading firearms may not be "antique firearms" under state or federal law, and may require certain firearms permits or licenses. Check with the Massachusetts Department of Public Safety or U.S. Bureau of Alcohol, Tobacco, Firearms and Explosives if you are uncertain.

This is not the complete law and is subject to change. Refer to several provisions of M.G.L. c. 131 and the Code of Massachusetts Regulations, 321 CMR.

Regulations as of 6-16-11.