[Ron Wood]

Richard,
The entire web (or bulkhead as you call it) and the support for the recoil lever pin has been fabricated and set into the 1900 frame with dovetails at the front (see inset) and rear. Charlie Kenyon provided detailed line drawings of the insert in one of his articles in the series he wrote for "The Gun Report" some years back. It is the same device that was in a prototype piece that has been attributed to the Dutch, in fact some give the Dutch credit for inventing the coil spring action (but was probably something developed by DWM in response to the Dutch request for improvements).