Has anyone successfully made a barrel locking mechanism for their springer?

Way back when, some shops fitted breech latches to the FWB 124 to help with their weak lockup mechanisms. Google for a pic. Unfortunately the breech shim arrangement is so junky that I doubt it solved the issue completely. 

The Diana's have the same ball bearing detent, but much better executed. The FWB latch setup may be very similar to fit to the Diana. Never seen one in person, sorry I can't be more help