.40 S&W Ammo

What is .40 S&W?

.40 S&W (Smith & Wesson) was designed in 1989–1990 as a deliberate compromise. The FBI had adopted 10mm Auto after the 1986 Miami Shootout — the deadliest day in FBI history, where two agents were killed in a firefight that exposed the inadequacy of .38 Special revolvers. But 10mm at full power proved too much for many agents to handle, and the Bureau was downloading loads to reduce recoil. Those downloaded loads barely outperformed 9mm in a much larger frame.

Smith & Wesson and Winchester’s solution: take the 10mm case, shorten it by 7mm, reduce pressure slightly, and load it to specs that matched the downloaded FBI 10mm loads. The result fit in a 9mm-framed pistol with minimal modification. The .40 S&W was born in January 1990, and it moved from announcement to production in six months — one of the fastest cartridge-to-market timelines ever.

The FBI adopted it immediately. So did most major U.S. law enforcement agencies throughout the 1990s and 2000s. For about 25 years, .40 S&W was the dominant U.S. police cartridge.

The FBI switch — and what it actually means

In 2014, the FBI announced it was switching back to 9mm. The reasoning was extensively documented: ballistic testing showed modern 9mm JHPs performed comparably to .40 S&W in terminal effectiveness, while 9mm offered higher capacity, lower recoil (enabling faster accurate follow-up shots), and lower cost for training. The FBI published a lengthy technical memo supporting the decision.

Most agencies followed. The institutional shift was decisive enough that .40 S&W stopped being specified in new department RFPs. Glock production of .40 models slowed significantly.

The practical result: a large surplus of used .40-caliber pistols hit the market at discounted prices. A used Glock 22 or M&P40 that might have sold for $500 when new often runs $350–400 used. The guns themselves are identical in quality — only the caliber fell out of institutional fashion.

.40 S&W vs. 9mm: the honest accounting

Terminal performance in FBI-protocol gel testing is genuinely similar between modern JHP loads in 9mm and .40 S&W. The gap isn’t large enough to be a practical consideration. The .40 penalty is in capacity and shootability — two rounds less and more recoil affect real-world performance more than the marginal energy difference.

Where .40 still makes sense:

• You bought a used .40 pistol at a significant discount
• You need to make major power factor for competitive shooting
• You’re already proficient with the caliber and don’t want to retrain

Where it doesn’t:

• You’re buying new and selecting the caliber fresh — buy 9mm
• You’re running a budget training program — 9mm is cheaper

Ballistics data

From a 4-inch barrel:

FBI gel data

FBI protocol (10% gel, 4 denim layers, 4” barrel):

The 180gr HST and Gold Dot perform very well — consistent expansion, deep penetration. This is legitimately good terminal performance, comparable to the top 9mm loads.

Brand guide

Federal HST 180gr — the LE standard, same load issued to federal agents. Deep penetration, consistent expansion. ~$0.85–1.20/rd.

Speer Gold Dot 180gr — bonded construction, high retained weight. The other half of the law enforcement market. ~$0.85–1.20/rd.

Federal HST 165gr — slightly higher velocity than 180gr, still reliable expansion. ~$0.85–1.20/rd.

Winchester PDX1 165gr — bonded bullet, wide distribution, solid performer. ~$0.80–1.15/rd.

Hornady Critical Defense 165gr FTX — polymer tip for reliable expansion, widely available. ~$0.80–1.15/rd.

Blazer Brass 180gr FMJ — cheapest reliable practice ammo. ~$0.28–0.40/rd.

Federal American Eagle 180gr FMJ — brass case, cleaner than steel or aluminum, consistent. ~$0.30–0.42/rd.

Speer Lawman 180gr TMJ — total metal jacket (fully enclosed base), popular for indoor ranges with strict lead rules. ~$0.35–0.48/rd.

Price guide (2025–2026)

.40 S&W practice ammo costs roughly 25–35% more than equivalent 9mm. If you shoot 500 rounds a month for training, that’s a meaningful number.

Firearms chambered in .40 S&W

• Glock 22 (full-size, 15+1), Glock 23 (compact, 13+1), Glock 27 (subcompact, 9+1), Glock 35 (competition long slide) — the most common .40 platforms; excellent used market availability
• Smith & Wesson M&P40, M&P40 2.0 — ergonomic, widely used by law enforcement
• Sig Sauer P226, P229 — DA/SA, excellent build quality, popular with federal agencies
• HK USP .40, P2000 — German manufacturing, DA/SA
• Springfield XD/XDM .40 — higher capacity than many, grip safety
• Walther PPQ M2 .40 — excellent trigger for the platform
• Beretta 96 series — .40-caliber version of the 92 series, 12+1
• CZ 75 .40 — less common but excellent ergonomics

The Glock 22 and M&P40 dominate the used market — ex-police guns at significant discounts, generally well-maintained under armorer programs.