I have to wonder why they think wood won't stop a bullet. Maybe 3/8 plywood won't, but then neither will the sheet steel used in car bodies.
I've dug enough bullets out of trees I cut for firewood to know that they'll penetrate maybe an inch or two into pines. Something at the upper end of the strength/density scale, like mountain mahogany
https://www.fs.fed.us/wildflowers/pl...difolius.shtml which is so dense that it doesn't float, and is real good at dulling chainsaw blades?