"Got a thick membership directory in the mail that was headed for recycle, so why not...shoot some .32 ACP into it. All... penetrated just over an inch..." [ligonierbill]
Got some soon to be discarded 'stuff' --- a thick trade paperbound book 1 & 1/4 " thick, plate steel housing .39" thick, a 1" board and finally a 2"x10" board (stacked one on top of other). Shot a Walther PPK, (manufactured 1933), one round S&B 32ACP ammo, 73 gr fmj bullet, see pics, went thru the book, the plate steel, the 1" board, and finally stopped a 1/2" into the 2"x10" board.
"Per M----the .32 hits like a brick through a plate glass window." [batmann]
Well I should think so.