Hi BP

I've just been to strip mine for the details you're missing above for 198 (I presume you picked up the confirmation of the other numbers from a post of mine some years ago?). I'm happy confirm that the Breech Block and Piston Ext are also number 198.
I'm intrigued to note that the 2nd barrel exist elsewhere. It would be good to be able to reunite it with the gun one day!

ATB, Kev