wow what are you guys shooting? ever shot a book?
as a drywall-er of over 25 years i know all about Sheetrock and no it wont stop buck shot, but a wall that consists of two layers of drywall and if a stack of books were placed on other side i would be hard pressed to think it would not stop a .33 cal. pellet then again i wouldn't put a child's life at risk to prove that!
it seems every few weeks we discuss the over penetration thing and we go back and forth some have even said place a stack of dimes in a shell. I am kinda tired of this really. Use your best judgment and hope you never have to find out. and if you are scared of over penetration get a sword there is no right answer i use slugs and 00buck i have no children or others in the house.