This conversion kit includes everything you need to easily convert your existing upper to a dedicated .22LR platform. Once you purchase a compatible magazine, you'll be ready-to start shooting. For optimal performance, it is recommended to use a round style hammer, as notched hammers can lead to function issues. Additionally, using 36-grain plated nose bullets has shown to provide the best reliability and performance. Upgrade your upper with this conversion kit to enjoy the versatility and efficiency of .22LR shooting.