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4 important factors in the 9mm pistol debate

The finished shape of the bullet probably has more to do with the overall effect — bullets with sharp edges can slice blood vessels rather than tear them, causing a more rapid bleed out

The latest fad in law enforcement is to change from a larger sidearm caliber to the 9mm. I’ve always believed drilling bigger holes does a better job of stopping dangerous adversaries, but I’ve spent more years packing a 9mm pistol than any other caliber, and never felt under-gunned.

The answer on whether or not an officer — or legally armed citizen, for that matter — should select 9mm over another cartridge is, “it depends.” It depends on what gives the operator the highest level of confidence in winning the fight.

That having been said, let’s examine some of the factors which weigh into the decision to go with one cartridge over another.

1. Modern bullet technology has made the 9mm as effective as bigger calibers.
The “high-tech 9mm bullets” argument only holds water if you pretend the improved bullet technologies haven’t been applied to all other pistol calibers. Indeed, modern 9mm projectiles — like bonded designs or the all-copper Barnes TAC-Xp hollow points — do deliver much more reliable expansion and penetration characteristics than older designs.

But .40 and .45 caliber TAC-XPs give proportionately better expansion/penetration than older designs in those calibers.

A “new” 9mm design might equal the performance of an older .45 design, but falls just as far behind when you compare apples to apples. Police bullets commonly need to defeat automobile glass and this is a simple matter of mass; the bigger bullets will always do more damage to the target after being shredded by the glass.

Let’s compare the three most common police sidearm cartridges in the most common sidearm. I’ll use the velocity values from Black Hills Ammunition’s line of Barnes Tac-XP bullets in the chart because I have the correlating gelatin expansion/penetration data. Is the bigger hole worth the added recoil?

The volume of the permanent cavity calculated from expanded diameter and depth of penetration. Check out the chart below, and click on it if you would like to see a larger version.


I will always carry the largest drill I can, so my choice for open/duty carry is either a .45 for social work or a full-power 10mm in the boondocks. When I need a small pistol for concealment, a 9mm with high-tech ammo will do.

2. Less recoil makes the 9mm easier to shoot, especially for “small statured” officers.
Shooting — including the recoil factor — is primarily a mental exercise, not physical. I recently saw a small-statured female go through basic police training with a Glock 22. Her hand was almost completely around the right side of the pistol for her finger to reach the trigger. She wasn’t top-gun in her class — and needed remedial training to pass — but pass she did. Like other aspects of a program skewed in favor of big guys, she mentally decided to succeed — and did.

Would the lower recoil of a 9mm make the difference between passing and failing with some trainees? Maybe. A smaller grip frame would help marginal performers more than lighter recoil. I’ve seen some damn small shooters handle a .45 caliber single-stack pistol like a champ.

If we ever see a modern striker-fired pistol with a single-stack magazine, small officers will have the most tractable sidearm possible, allowing any caliber to fit their hand. Are you listening Glock? For those who can handle a .45 effectively, why not carry the most power available.

3. The 9mm pistols have a higher capacity, so pack more rounds for the fight.
Again, assuming you’re using Glock pistols, a fully loaded Model 17 (9mm) equals 18 rounds. You have 16 rounds with the model 22 (.40 S&W) in the same size package.

If you can’t solve a street shooting problem with 16 rounds of .40, I seriously doubt two additional rounds of 9mm will make much difference — reload!

4. 9mm ammunition costs less, allowing us to shoot more.
Precious metals sell by the pound. The less metal you use to make a cartridge, the less it will cost.

I consider lead, zinc, copper, and tin to historically be the most precious metals (the base metals needed to manufacture weapons ranging from bronze-age swords to modern firearms ammunition). History teaches us that those people with the most lead/zinc/copper/tin tend to take all the gold and silver they desire.

The bottom line? Shot placement trumps all — a 9mm bullet hitting center-mass is more effective than a .45 on the edge. The 9mm represents the smallest cartridge suitable for a duty pistol — it is adequate. The .40 S&W drills a significantly bigger hole, at the expense of more wear and tear on the pistols and complaints about “snappy” recoil.

The venerable .45 causes the biggest wounds and many find it more comfortable to shoot than a smaller .40 caliber pistol. The .357 Sig and .45 GAP cartridges represent a very small percentage of police pistols and their small numbers result in greatly increased ammo costs.

Finally, because pictures are worth a thousand words (and that is about what my word count is for this article), check out the bullet/gelatin images from Black Hills Ammunition (loaded with Barnes all-copper projectiles) in the Related Articles box above and to the left. Those links are titled, 9mm Luger 115 grain Tac-XP +P, .40 S&W 140 grain Tac-XP, and .45 ACP 185 grain Tac-XP +P. Inspect those, consider the above, and make the choice that’s right for you.

Dick Fairburn has had more than 26 years of law enforcement experience in both Illinois and Wyoming. He has worked patrol, investigations and administration assignments. Dick has also served as a Criminal Intelligence Analyst, and as the Section Chief of a major academy’s Firearms Training Unit and Critical Incident Training program.