Won't fit bull barrels! - FAB Defense Ruger 10/22 Collapsible Stock Conversion Kit

This is probably the nicest stock I've seen for a 10/22. It feels great and the material feels solid.
I really liked it, and I wanted to keep it, but the barrel channel insert doesn't fit .920 bull barrels. You can remove the insert, but then you're leaving a hole that goes down into the hollow interior. Not a clean look and now debris can get in.
I was told you could flip the channel insert around and it would work, but it still doesn't fit my Green Mountain barrel.
I wish the company would offer a bull barrel channel insert as an accessory.