.380 ACP vs 9mm: Which Pocket Pistol Caliber Wins for Defense?
.380 ACP (9×17 mm) is a straight-walled pistol cartridge; 9mm (9×19 mm) is a tapered, longer round. Both fire 9 mm bullets, yet the 9mm packs roughly 30 % more powder and energy.
Shoppers eye the same micro-pistols—Glock 42 vs 43, SIG P365 vs P238—spot “9 mm” on the barrel, and assume the smaller .380 is “just as good” because it looks identical in photos.
Key Differences
.380 delivers 200 ft-lbs from a 2.7″ barrel with mild recoil; 9mm gives 300+ ft-lbs but jumps more. Mag capacity is equal in micro guns (6-8 rounds), yet 9mm ammo is cheaper and far more common.
Which One Should You Choose?
If you can handle the snap, 9mm offers deeper penetration and more load choices. Pick .380 only when ultra-light recoil or the tiniest locked-breech pistol is non-negotiable for pocket carry.
Will a .380 stop a threat?
Yes, with good shot placement and modern JHP loads, but it gives less margin for error than 9mm.
Can I shoot +P .380?
Only if the maker says so; most micro-.380s aren’t rated for it and will batter the frame.