S&W 15-22 magazine with the Catch22 adapter

This offers the best functionality with the Catch22 bolt catch. With the 15-22 magazine and adapter, you will have the exact same functionality as a standard. 223 AR.

The spring tension in the magazine is strong enough to reliably hit the bolt catch every time, and the follower sticks up high enough to ensure a solid lock up. 

The Catch22 magazine adapters (either stick-on or clip-on) allow you to use the 15-22 magazines in a standard AR. The 15-22 magazines are shorter front-to-back than a normal magazine and so the magazine adapters take up some of the slack that the skinny magazine in a larger mag well creates.