Hee hee! Those files DO heat up when your fitting those rails, don't they? Did ya make it one peice or two glued together? Keep us posted on your progress. :hatsoff:
Just a suggestion, when I made the catch for the cover on my .36 Lancaster I used an old cut nail. I forged the shank flat to make the spring and shaped the head to meet the contour of the but plate, filed a small offset to catch the under side of the but plate. I didn't have to temper the spring section as the natural give of the iron is plenty suficient for this use.