If you set up your Stevens for a kid and the rear stock is too long,
Look around for ATI's collasable M4 stock for H&R New England single shots.
I'm pretty sure they discontinued them but they fit the Stevens well, all you'll need is a slightly longer bolt.
(https://uploads.tapatalk-cdn.com/20200426/cc951b571de0da6fde1b3ed2fbaad4a5.jpg)