After marking out the action lines, I use the hack saw (fine teeth + fine cut) and cut down to within cooee of the mark and only forward to the rear of the receiver ring.

and a few minutes with a sharp chisel gets the inletting started.

Next step was to find the dimensions of the mag wall and start an undersized hole though the wood.

One hole at 24mm and the front three at 20mm had it started.

Finding out the back of the trigger group recess came next and again all cut undersize.

and a little chisel work had it opened up to where I would just get clearance vertically