I've heard of it but have never tried with my flintlock and patched round ball. I usually just shot for the head.
Historically,in the 1700's and early 1800's squirrel hunting was more a pest control measure than for the pot. Organized hunts among different "teams" to see who could take out the most of those little pesky critters were often held. In many cases the states or county governments offered bounties on "squirrel scalpes". This was done in an attempt to protect the agriculture in the area from an invasion of what must have been thousands of squirrels. I remember reading about one organized hunt in the early 1800's that supposedly killed 20,000.
Oops....I've wandered off the subject a bit. Below is an account from John J. Audubon and an accounter with Boone where he discribes a squirrel hunt with Boone "barking" squirrels. Click on note 27.
I read a article about bark'n when I was a kid in high school (in the 80s).
It read that they ate every part of the squirrel include'n the brains & cheeks, & by shoot'n the tree limb to kill the squirrel it didnt waste any meat.