Vern Humphrey
Member
You bring up a great point! If you take a look at the hole a projectile (bullet) makes, it's somewhat cylindrical shaped, right? (yes, I know, it's not perfectly straight, but in general... it's a 'tube' AKA, Cylinder) So, while the SURFACE area of that tube (cylinder) is the 'now-opened space, that didn't used to have a hole'... sure.. But.. the surface area of said 'cylinder' is in direct proportion to the diameter of the object that makes that hole. I know, I know... you don't want to quibble the math, I saw that, but my 13yo is bringing home geometry homework these days, and I get to step in when my bride lets me.
Well, maybe.
Try this -- shoot at a sheet of typing paper with a .22, then examine the hole.
First of all, there will be shreds of paper trailing backward from the hole. Put your finger over those shreds, pushing them back into position, and examine the hole.
You will see an irregular hole, much smaller than a .22 bullet, with tears radiating outward from the hole. (The diameter of the bullet is shown by the "scuff collar" around the irregular hole.)
This tells us how the bullet penetrated. The nose of the bullet touched the paper and stressed the fibers to the breaking point. The nose of the bullet entered the small hole and "shouldered" its way through, causing the radial tears.
This is somewhat similar to the way a round nose bullet penetrates flesh. The actual hole is smaller than the bullet. There will be no radial tears, however, because flesh is elastic and can give enough to allow the bullet passage.
This is why semi-wadcutters are so dramatically more effective than round nose bullets of the same caliber, weight and velocity -- they chop out a bigger hole.