I used to get these plates from a guy named Don Brown in Yakima (509-996-4191) who marketed a English Percussion rifle (Rigby?) kit, many, many years ago.
They are cast about .090" thick and as you can see from the upper left, I would file them to a skinnier oval, drill countersink & fit. Then you better run a border around your checkering, (PITA!) to make them look right. (Checkering around a tightly curved forend is it's own PITA! better add about $1000 to the job for plates, wedge & checker!)
Wedge casting I believe was from TOTW(?) about .100" thick and I would file the head to a miniture oval.
Lot's of handwork, Hardly anybody noticed! I'll see if I can photograph the chisel used to inlet through the forend.
Let me know if you alls have any luck getting some!
Can barely see in this pic, but show clearly in my Custom Rifles book.
