Svage 11VT with Choate Stock

I have a Savage 11VT chambered in 308 with the detachable box mag. I broke the gun down as I had the barrel threaded so I could install a muzzle brake and figured why not put on a Choate Tactical Stock. Like everyone else I had to modify the opening on the stock to fit the trigger housing. I head spaced the chamber and screwed the action and barrel into the Choate stock. The issue I am having is the detachable box mag won't click into place like it did with the original stock. It seems like it is so close but wont snap into place. Any suggestions or ideas from people who have had the same issue?

Use a washer under the rear of the mag frame.

I will try that Stangfish, I appreciate it!