Glock 22 Gen5
.40 S&W · 10-rd SKU
FN 510 Tactical
10mm
How .40 rose
.40 S&W appeared in 1990 as a shorter, more controllable alternative to 10mm. The FBI had adopted 10mm after the 1986 Miami shootout, then moved to reduced-power loads. .40 fit in 9mm-sized frames, and agencies across the country adopted it through the 1990s and 2000s.
How it fell
Bullet technology got better. Modern 9mm hollow points, tested against the FBI's standards for penetration and barrier performance, narrowed the gap with larger calibers. The FBI announced a return to 9mm in the mid-2010s. Its reasoning pointed to comparable terminal performance, lower recoil, higher capacity, and better shooter accuracy with 9mm. Many agencies followed. BulkAmmoFinder's history piece goes into the detail.
Who still carries .40
.40 remains in service with agencies that haven't transitioned, and with shooters who prefer the heavier bullet. Rather than guess at which agencies still issue it, the practical signal is simpler: Glock still makes the G22 Gen5, and major ammunition makers still load duty-grade .40.
The buyer's angle
- Trade-in pistols. When agencies switch calibers, used .40 duty guns come onto the market. Inspect them for wear.
- Holsters and magazines. Many holsters fit both 9mm and .40 versions of the same frame, because frame dimensions are often shared. Confirm fit for your exact model.
- Conversion barrels. Some .40 pistols can accept 9mm conversion barrels and magazines. This is model-specific, so check with the manufacturer.
- Ammunition. Defensive .40 loads from the major duty lines are still available.
And 10mm?
The FN 510 Tactical shows full-power 10mm is back in modern duty-style pistols. It's a niche choice for duty, but it's popular for woods carry and among shooters who want more power than .40.
Verdict
If you're choosing a new duty caliber today, 9mm is the default for good reasons. See our Glock 17 vs 19 and duty ammo guides. If you already own and shoot .40 well, nothing about 2026 makes your pistol less capable.
Frequently asked questions
Why did agencies drop .40 for 9mm?
Better modern 9mm hollow points narrowed the performance gap. 9mm also offers lower recoil, more capacity, and less wear on guns. The FBI's return to 9mm in the mid-2010s pushed many agencies to follow.
Is .40 S&W still made?
Yes. Pistols like the Glock 22 Gen5 are still in production, and major manufacturers still load .40 S&W defensive and practice ammunition.
Is .40 more powerful than 9mm?
It fires a heavier bullet and has more recoil. Whether that translates into better real-world performance with modern hollow points is disputed. The faster, more accurate follow-up shots of 9mm are a big reason for the switch.
Should I buy a surplus .40 police pistol?
Trade-in .40 pistols can be good values, but inspect wear carefully and factor in holster, magazine and ammunition costs.
Keep reading
DutyHandguns earns a commission on some purchases made through links on this page, at no extra cost to you. Availability and pricing change often — always confirm on the retailer's page. Firearms ship only to a licensed dealer (FFL); you are responsible for complying with all federal, state and local laws. Nothing here is legal advice. Agency policy, not this site, governs duty equipment for sworn personnel. Get professional training and store firearms securely.