The 513T Buttplate is steel and the 521T Bakelite. You can find them but the used ones rarely fit and the reproduction don't have the same look being made of plastic or poured epoxy. Luckily I have all the pieces so I will be able to fit the old one back together with a little patience, color matching with the epoxy, and recutting of the ridges with my checkering tools and the breaks won't be noticeable.