Give some thought to your end use for the rifle to see if you really need the detachable box mag. If you can live with the hinged floor plate, which is an improvement over the original mauser design ( exc 1909 Argentine, of course), then you should be able to open areas up as needed and fill voids (especially at rec ring) with a compound such as Devcon 10110, which would come pretty close to matching the gray colors in the lam stock. Make sure you have some clearance between top of bottom metal (mag well top edges and top of pillar) and bottom of action. Worse case, you can file down about .010" off top edges of bottom metal afterwards to restore clearances. As Dk Phillips says, tape, modeling clay and release agent are your friends, as is the most important part ...patience.