The choice between .380 ACP (Automatic Colt Pistol) and 9mm largely depends on personal preferences, intended use, and specific circumstances. However, here are a few factors to consider:

1. Size and Concealment: .380 ACP handguns are often smaller and more compact than their 9mm counterparts, making them easier to conceal. If discreet carry or deep concealment is a priority, a .380 ACP pistol may be a better option due to its smaller size and reduced weight.

2. Recoil and Shootability: The .380 ACP typically generates less recoil compared to the 9mm, which can make it more manageable for shooters with limited hand strength or those who struggle with recoil control. This can result in improved accuracy and faster follow-up shots.

3. Capacity and Firearm Options: In general, 9mm pistols offer higher magazine capacities compared to .380 ACP pistols. The larger cartridge size of 9mm allows for more rounds to be loaded into a magazine, providing a greater number of shots before needing to reload. Additionally, the market for 9mm firearms and ammunition is larger, offering a wider range of options in terms of firearm models, accessories, and availability.

4. Stopping Power: While the 9mm typically offers greater stopping power and penetration compared to .380 ACP, the effectiveness of a handgun for self-defense ultimately depends on shot placement, bullet design, and other factors. Both calibers can be lethal and incapacitating if proper shot placement is achieved.

It's essential to consider your individual needs, proficiency, and preferences when choosing between .380 ACP and 9mm. If maximum stopping power and capacity are your primary concerns, the 9mm is generally considered a more potent and versatile choice. However, if concealability and recoil management are important factors, a .380 ACP pistol might be a suitable alternative. Ultimately, proper shot placement and regular training are crucial regardless of the chosen caliber.