Semi-automatic rifles are firearms that automatically reload after each shot but require the shooter to pull the trigger for each round fired. This means that after firing one bullet, the rifle uses the energy from that shot to eject the spent cartridge and load a new round into the chamber, allowing for quicker follow-up shots compared to manual-action rifles. These rifles are popular for various uses, including hunting, sport shooting, and self-defense. They come in various calibers and designs, with some models being based on military firearms, such as the AR-15 or M1 Garand, while others are designed specifically for civilian use.