Arrow diameter and real world penetration

[old_goat2]

I like them, they make the deer look bigger in the pictures when you have the arrow in view with the deer!

[warden415]

lol @ old goat

[Stumpkiller]

I shoot wood.  I have noted a real difference between the 23/64" prallel shafts I used to use and the 11/32" tapared down to 5/16" that I currently shoot.  

Much of this could be the head - glued on the 23/64" shaft there was usually a ridge of tapered wood behind the head.  With 11/32" it is smooth or even lesser diameter than the rim of the head.

[LKH]

The idea that blood lubricates the fat shaft so it doesn't matter is myth.  Anything that touches the shaft has friction, even liquids. (see what happens to flow out a hose when you go from 50 to 75 feet)  The fatter shaft will have more pressure to the side as it moves through the animal.

All that said, with deer size game you won't be able to tell unless you hit shoulder.