In the September 2012 issue of the American Rifleman magazine an article titled Handgun Stopping Power, the author, Richard Mann a Field Editor, compared the ballistics of calibers from .22 to .45 ACP. The author fired 100 rounds into 10% ballistic gelatin. 23 of these rounds were 9mm. He tested for velocity at 10 feet, penetration and expansion. He did not specify what guns were used to fire the rounds. He does on occasion show results for different length barrels for selected rounds.
He went through the logic of his protocol for determining what performance results were satisfactory in his opinion. He concluded that the minimum velocity of a round should be 1000 feet per second, that penetration should be at least 13" and expansion should be at least 1.5 times the original diameter of the round irrespective of your caliber of choice. Another approach he suggested for using his data was to compare you favorite round to the averages for its caliber. Obviously when one is analyzing raw data you can develop your own criteria and analyze accordingly.
For the rounds tested, his results showed about 1/3 of the 100 rounds tested met his suggested standard. Relative to the 9mm rounds tested, his results disclosed that 11 of the 23 rounds tested (including multiple same rounds in different length barrels) met or exceeded his specifications. Using his specs, the Corbon 100-gr +P; 2 DoubleTap rounds, a 80-gr and a 124-gr; Federal 115-gr JHP; Remington 115-gr JHP; Remington 124-gr Golden Saber +P; 2 Speer 124-gr HP; Winchester 124-gr JPDX1 HP; and Wilson Combat 124-gr XTP. Some of these same rounds did not meet his standards when shot out of a medium or short barreled gun. The Hornady Critical Defense 115-gr was just short of his standards. I utilize the Hornady and the Federal ammo in my defensive handguns so I am one out of two based on this analysis. He did not test the relatively new Hornady Critical Duty round.
If you can obtain a copy of the article he discusses his thoughts on the differences in killing a bad guy vs stopping the bad guy. His opinion is it is all about stopping the bad guy before the bad guy can harm you. He cites several well known sources of information on the subject. He points out that he could not distinguish whether a round nosed .32 or a round nosed .45 ACP made cavities in the gelatin when the rounds passed completely through the gelatin. He also points out and cites other studies that show that there is documented evidence of one shot stops with all calibers from .22 to .45 ACP. Some of his test results are surprising and others were predictable. All in all the article is worth the read.
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The guys at the LGS said it would penetrate vests with no problem as well.