Wasn't much going on today so I decided to shoot some birch arrows (5/16 shaft w/ 125 grain field points) on my side yard Archery Range. I used my homemade 33 pound fiber backed laminated birch and maple longbow and shot from 15, 20, and 25 yards. On (what became my last arrow of the day after about 2 1/2 dozen arrows) I was finishing up from the 25 yard mark when I let loose one arrow that went high and stuck in the backstop.
I decided to mark the penetration of the field point to see just how deep it went into the 1/2" plywood that was backed with a 2x4 behind this part of the sheeting backing. (Approximately 2 inches)...
The red mark on the arrow below show the penetration. I don't think that's to shabby from a 33# @ 28" pull from a home made lite longbow at 25 yards away. Naturally the shot was not intended to go there - as I would have preferred it to be in the target. Still, this is good food for thought of just what a lite pull weight longbow is capable of from 25 yards out on a (well in this case) wood target.
I make the penetration just at 1.5 inches from 25 yards. Had the 2x4 not been behind the plywood where the arrow struck, it most likely would have traveled completely through (or very close to traveling through) the 1/2" plywood.
As a side not, I have shot through this backstop at time with more powerful bows (42+ pounds and up) from 25 yards. However, not to worry as there's another storage shed and bushes behind the backstop - and once an arrow has traveled through the backstop I have found them just laying in the bushes with the feathers not in very good shape and the arrow needing new feathers.