How do 9mm and .40 S&W compare?
These are distinct cartridge designations, not interchangeable ammunition. A shared firearm-model family does not establish chamber, magazine, or component compatibility. Verify the exact ammunition designation against the firearm manufacturer's instructions.
This page does not infer a duty or defensive use. A comparison needs a stated criterion and evidence supporting that criterion.
Agency history and evidence boundaries
An agency claim needs the exact report, date, participating population, test protocol, and results. An agency procurement decision does not establish a cartridge-wide performance winner or suitability for a civilian firearm.
Cost per round and used-firearm prices
Use 9mm FMJ listings and .40 S&W FMJ listings to examine eligible tracked offers. Check exact product identity, package quantity, observation time, and the disclosed cost basis.
Divide each listed offer price by its round count. Delivered-cost comparisons additionally require known shipping and tax on the same basis. Unknown shipping does not establish a delivered-cost winner. Historical observations are not currently purchasable offers.
This page supplies no dated offer dataset establishing a widening price gap, overlapping hollow-point prices, or a production-volume explanation for specific retail prices. It does not predict future price or platform support.
IronScout's ammunition listings do not establish used-firearm prices, condition, or years of ownership savings.
Ballistic and terminal-performance boundaries
A checkable comparison needs exact load identifiers, test barrels, ammunition lots, measurement methods, and conditions. Bullet mass and sourced velocity support energy arithmetic, not a universal expansion or penetration result.
This page supplies no matched terminal-performance series establishing that every modern hollow point meets an FBI protocol or that the cartridges have equivalent effects. Verify the exact manufacturer's construction and performance claims separately.
Recoil and firearm durability
A calculation of free recoil is not a measurement of how a person experiences a particular firearm. This page supplies no matched recoil, fatigue, split-time, or training study establishing a universal cartridge winner.
This page supplies no comparative durability test or causal evidence linking a cartridge to an agency transition.
Follow the exact equipment manufacturer's operation, inspection, and maintenance guidance. This article provides no firearm-use or repair instructions.
Capacity and platform availability
Verify the exact firearm model, variant, magazine, chamber designation, and manufacturer specifications. A model-family name does not establish capacity across generations or jurisdictions.
Capacity arithmetic alone does not establish a defensive outcome.
This page supplies no manufacturer or sales census establishing the largest current lineup, annual decline, or universal component availability. Missing tracked listings do not prove that no product exists.
Comparing by a stated criterion
A comparison must disclose its criterion before naming a winner. Eligible offer arithmetic can establish a scoped cost-per-round result. Accuracy, recoil, durability, and terminal performance require comparable evidence that this page does not supply.
Related comparisons
- 9mm vs .45 ACP — The classic big-bore comparison
- 9mm vs 10mm Auto — Full-power semi-auto comparison
- 9mm vs .380 ACP — The carry caliber size debate
Related caliber pages
- 9mm ammo prices — Eligible tracked listings
- Lowest observed 9mm prices — Historical statistics, not current offers
- 9mm price history — 30-day pricing trends
- .40 S&W ammo prices — Eligible tracked listings
- Lowest observed .40 S&W prices — Historical statistics, not current offers
- .40 S&W price history — 30-day pricing trends
- 10mm Auto ammo prices — The .40 S&W's parent cartridge
Search 9mm by cost per round → | Search .40 S&W by cost per round →