M5 compatible hinged floorplate with integrated box

I'm building a custom set up and would like to find an M5 compatible hinged floor plate where there is a magazine box that stays with the floorplate and the z spring doesn't pop up through the box.
I have a Browning A bolt composite stalker I bought when I was 14 that has this set up. When you push the button in front of the trigger guard the floorplate and magazine swivel out as one and can be loaded/unloaded. The ammo lifter and spring assembly does NOT pop out the top. I'm having a hard time figuring out online if some of the M5 inlet floorplate designs just open and dump all the rounds out or if they have a magazine box if the z spring and lifter pop out the top like a jack in the box.
Any advice would be appreciated.
Thanks.

I don't think it exists.

That's a unique to Browning feature for a DBM. A solution to people somehow losing their magazines while hunting. Carried lots of different DBM rifles over the years and never lost a mag but heard of several that did. I suspect more than likely that they did't have them fully installed.

I have only ever seen that on the brownings ,specifically my A bolt rifles.