When I got my XLR Carbon Chassis, I had a little issue with the bottom bolt release, but XLR Industries remedied the issue so everything is gravy now.
The switch just behind the mag release is what activates the bolt release for the Savage 10 bottom bolt release. The system works perfectly and I'm pretty happy with it.
There's a notch cut out in the trigger slot as well.
The chassis for Savage's bottom bolt release, and the chassis for Savage's top bolt release.