For most buyers, 9mm is the correct answer — and the data supports it. Modern 9mm defensive ammunition from Federal HST, Speer Gold Dot, and Hornady Critical Defense performs comparably to larger calibers in terminal ballistics testing while offering higher magazine capacity and lower recoil. Law enforcement agencies including the FBI, which transitioned back to 9mm in 2015 after years on .40 S&W, reached this conclusion based on extensive ballistic research. For general purpose, defensive carry, and home defense, 9mm hits the best combination of performance, capacity, and shootability.

Striker-fired pistols use a spring-loaded striker that is partially cocked by the slide cycling and fully released by the trigger pull. The trigger pull is consistent from shot to shot — the same weight and travel every time. Glock, Sig P365/P320, Smith & Wesson M&P, and Springfield Hellcat are striker-fired. Hammer-fired pistols use a physical hammer that is cocked either by the slide (single-action) or by the trigger pull itself (double-action). A hammer-fired DA/SA pistol has a heavier, longer first trigger pull that lightens significantly for subsequent shots after the slide cycles. CZ 75, Beretta 92, and Sig P226 are hammer-fired DA/SA designs. Neither is inherently superior — striker-fired platforms have a simpler manual of arms and consistent trigger pull, while hammer-fired platforms appeal to shooters who prefer a visible hammer and DA first-shot option.

Standard capacity for a full-size 9mm pistol is 15-17 rounds. Compact carry pistols typically hold 10-15 rounds. Subcompact pocket pistols hold 6-10 rounds. For home defense, a full-size pistol with a standard capacity magazine is the practical choice — capacity is an asset when you do not need to conceal the firearm. For carry, the balance between capacity and concealability drives most buyers toward compact platforms in the 10-15 round range. Several states restrict magazine capacity to 10 rounds regardless of the pistol's design — verify your state's laws before purchasing extended magazines.

At the federal level, no special license is required beyond passing a standard background check through an FFL dealer. Semi-automatic pistols are Title I firearms — no NFA registration, no tax stamp, no ATF approval wait. Several states impose additional requirements including waiting periods (California, Florida, Hawaii), handgun safety certifications (California, Massachusetts, Maryland), or permit-to-purchase requirements (Illinois, New Jersey, New York, Massachusetts). Always verify your state's current requirements before purchasing.

Reliability at this price point is broadly excellent across major manufacturers. Glock pistols have the longest documented track record of reliability in sustained law enforcement and military use. Sig Sauer's P320 and P365 series have demonstrated strong reliability with tens of millions of rounds through military and law enforcement contracts. Smith & Wesson M&P series pistols are among the most torture-tested platforms in independent testing. CZ pistols have a strong reputation for accuracy and longevity. At the $400-$700 price range where most of these pistols sit, reliability differences between major brands are marginal — buying from any of these manufacturers and maintaining the pistol properly produces a reliable defensive firearm.