IV. Comparative Firearm Information

G. Calibre Issues

7. 9mm v. 10mm High Performance Ammunition Tests

by Marty Olsen (olsen@gilbert.geology.yale.edu)

I'm sure we've all heard that "10 mm is an overpenetrating round," and "147gr 9mm don't have enough velocity to expand..."

I wanted to see for myself, using the best testing medium that my poor graduate student lifestyle could afford : Wet phonebooks. For this test, a stack of fully soaked New Haven Yellow Pages were placed downrange at 10 yards. Bullet impact was perpendicular to the page surface.

The following factory rounds were tested :

Depth of penetration, retained weight, and final diameter were all measured. A 10mm Delta Elite and 9mm Sig-Sauer 228 were used.

RESULTS (averages of two or three shots)


Bullet 	  Retained Weight  Final Diam.(% Expansion)  Depth of penetration
9mm 124gr SF	| 122.7 gr	|  .652" (83.05%)	|  5.75"
9mm 147gr BT	| 147.3 gr *	|  .651" (82.96%)	|  7.38"
9mm 115gr ST	| 116.1 gr *	|  .621" (74.44%)	|  6.62"

Bullet 	  Retained Weight  Final Diam.(% Expansion)  Depth of penetration
10mm 200gr BT 	| 199.7	gr	|  .691" (72.75%)	|  6.5"
10mm 180gr SF	| 180.2 gr *	|  .653" (63.25%)	|  6.38"
10mm 180gr HS	| 181.1 gr *	|  .681" (70.25%)	|  6.5"
10mm 175gr ST	| 169.3 gr	|  .687" (71.83%) 	|  7.75"

* Some phone book material wedged in expanded bullet, assume nearly total weight retention.

Final diameter measured w/ micrometer; due to non-circular nature of most of the expanded bullets (i.e. the "talons..."), these data should be taken w/ a grain of NaCl.

Observations

As a 'control,' a 124 grain semi-jacketed flat point was fired. These suckers tore through at least 20 inches of phone book...

*All* of the bullets expanded beautifully, and in fact look just like those shown in the magazine ads! Buy a raffle ticket today!

Depth of penetration was determined by measuring the distance from the initial impact surface to final resting spot of the front of the bullet.

I conclude from these data that the 10mm's reputation as being an "overpenetrator" is a load of crap. It seems that bullet construction and design play a far more important role in determining penetration depth than caliber alone (As the 9mm flat point clearly shows.)

I hope you all find this little experiment to be as interesting as it was fun for me to perform!

P.S. Anyone notice the clever use of subliminal advertising? ;-)

Martin P. Olsen (whose favorite .SIG is a 228 ;-)