Wooden Patchbox Lid Installation: 

I scratched a line on the inside of the buttplate to locate the dovetails of the patchbox onto the plate. Then I removed the plate and cut out this area.

After making a series of cuts, I then placed the plate back onto the rifle and filed this area flush with the stock. 

Then I slid the lid into the stock and made adjustments with my file til it fit nicely. 

To determine where the leading edge of the patchbox lid would be, I used the Golden Means gauge. I measured from the lock finial to the end of the buttplate. This was the "5" measurement. Then I flipped the gauge and this gave me the "3" measurement for where the front edge of the lid should be.

I then marked this on the lid and measured the width of the flats along each side of the patchbox lid. 

Then I removed the excess wood from the lid.

The end of the patchbox was filed flush with the end of the buttplate. Then I slid the lid out ~1/16" ,the width of my brass plate for the end of the lid and filed this flat again. Now I have the thickness of my end plate exposed. Except in this case, I did it so I would end up with 1/64" overhang by the lid plate so when I filed it later, it would blend in with the butt plate better. 

I marked the thickness of the lid from 3/8" down to 1/8". I filed the excess wood off to create the taper of the lid. Once this was done, then I divided the width into thirds.

I rounded the lid to these lines and then divided it into fifths and did it again. This gave it a nice rounded surface.   Note, I drew a line 1/16" up along the edge so I had a nice square edge which I can smooth out later.

Found a piece of scrap brass and traced a rough outline on the brass and cut it down. I located where I wanted the two screw locations. Then I epoxied the plate to the end of the lid. Drilled a 1/16" pilot holes into the brass and lid. Then I drilled clearance holes for the #4 - 1/2" screws. I heated the brass plate and removed the brass from the wood. Cleaned off the epoxy and then countersunk the screw heads. Then I mounted the plate to the lid. 

After that, I filed the brass to conform to the shape of the lid and then fit the lid and brass plate to the stock. 

Now I can file the top of the brass to conform to the shape of the lid. 

Once this was done, then I filed the brass of the lid plate and the butt plate together to make a better transition between the two pieces.

Now I'm ready for the lid latch. For this I inlet the latch into the lid till the latch end was flush with the surface of the lid. Note; The whole latch, except for the 1/2" of the latch was inletted. I used a #56 drill bit to drill 1/2" into the recess so I could drive the latch into the lid. This meant I had to remove brass under the latch for it to rise when lifted. 

A recess was also inletted into the stock for the lid latch, too.  Then with a lot of trials and filing of the latch, it eventually latched and caught on the inside edge of the buttplate and held firmly.

Next I will gouge a thumb notch on the lid so it can be grasped to remove the lid. 

Here is the rifle at this stage.