A typical Mauser trigger guard has a detachable floor plate, but you know what? We can hinge and latch it.
First, we need to cut off the extra metal and dress it down.
Then we can cut out the hinge, shape it, and solder it into place.
Next comes the hinge slot.
We can now make the latch. Milling the slot comes first; we can then fit the latch into place.
A small spring provides the tension and that's the latch.
-- Larry Potterfield