Ronvella/Bramble- Thanks guys thats the type of info I am looking for. I'd love to see those pics too. I'm hoping for a similar outcome. The only concern I have is that my barrel shank will be .904 and once reamed the rim of a 12ga is .880. so there is not much left of the new barrel. I realize this area is surrounded by the 1.116 inch monoblock and extractor but its still thinner than I'm accustomed to. I've had this ER shaw 12 ga barrel for ages and was planning on using it on a SS Highwall I was scalling up. Now I think I'm going to order its mate and use it for the DR.

Addendum- ER SHaw has no barrels in 12Ga for 6-9 months so I ordered them from Pac-NOR.
Finished the Zaballa monoblock this morning. I bought a 10 inch .906 chucking reamer( cut it down to 5 inches OAL) and went very slow with lots of coolant to ream the chambers, then counterbored and threaded the chambers 15/16X32. Finally faced the action with a End Mill. Whole process took 2 hrs. Looks great too! Took pics but dont know how to post them here yet.-Rob