Bramble- Very Interesting and good approach. I'll bet running that tap in by Hand was fun at the end. I was thinking of just single pointing it myself. I assume you used a T wrench on that brass mandrel to wind it into the monoblock. Can you elaborate further? By the way how much larger in diameter did you leave your barrel to allow for the peening to conceal the joint? Did you glassbed the Zabala stock or reinforce it further? I appreciate the opportunity to pick your brain.
Finally, with all the TSA Airline issues with guns over .50 caliber and various Country restrictions, it may be very hard in the future to take any of our beloved big bores to Africa or Australia. Not so the 12Ga. Its legal everywhere. My creation is a simply way to get basically .458 Lott performance with a pre-Expanded bullet ( .458vs .729). I also engrave my Rims with 12GaFH and SHOTGUN so that there can be no regulatory confusion! Heck Its just a Brass/all weather 3.5 inch shotgun-see it says so on the rim! With Aluminum bullets its ECO friendly TOO!-Rob