Some things you CAN hunt with a pistol: bear, coyote, fox.
There is no person protection provision allowing you to carry a handgun while hunting even for LEOs. It is strictly prohibited during the shotgun season for deer.
That reference to .38 caliber mention before refers to regs about hunting at night in a wildlife Management Area during upland bird season.
Just remember that the abstract you get at the clerks office or sporting goods store is only excerpts from the law and not all the laws .Best advise is if you're in doubt call Fish & Game, or your local EPO.
I don't have my book with me now, so i'll give a half assed answer, much of this is covered in CMRs. But there are the following MGLs...
Chapter 131: Section 67 Rifles, revolvers and pistols; caliber
Section 67. A person shall not use or possess, where birds or mammals may be found, any rifle chambered to take larger than twenty-two long rifle ammunition, or any revolver or pistol chambered to take larger than thirty-eight caliber ammunition between the hours of one half hour after sunset to one half hour before sunrise of any day throughout the year.
Chapter 131: Section 70 Hunting with rifle, revolver or pistol, or by the aid of a dog; primitive firearms
Section 70. A person shall not, during the open season when deer may be hunted lawfully with a shotgun, hunt a bird or mammal with a rifle, revolver or pistol or by the aid of a dog, or have in his possession or under his control in any wood or field, a rifle, revolver or pistol, or a dog. Nothing in this section shall be deemed to prohibit the use of dogs to hunt waterfowl in coastal waters and salt marshes during the open season on migratory waterfowl.
Notwithstanding the provisions of this section, the director may authorize the use of primitive firearms or shotguns with a rifled bore for hunting during any period when deer may be hunted by means of a firearm under rules and regulations promulgated in accordance with section five.
More to follow once get my hands on my book...
fyi this is the book http://www.gouldlaw.com/showprod.asp?prodinfoid=77 good thing to have esp if you're a hunter ed instructor