alyce-james, thank you. I'm not privy to anything but scarce information on T. Moxham in fact I've never seen an example of his work. My compliments to your diligent research.
Pushboater, thank you. Yes, I've made 10+ swivel breech actions and to the best of my abilities, my version of the Dave Waters actions are dimensionally correct give or take .003" on dimensioned parts. I make the tumbler link a bit differently than Dave suggests and I find adjustment is necessary on the main spring clevis block in order to achieve a 10 pond pull (on the cock) but that variance could be due to the L&R QC on their springs. The L&R main springs vary greatly and I question why I continue to buy their products.
I recently built a single barrel rifle inspired by John Armstrong (.45 cal) and bought the gun builders lock from Jim Chambers and it was flawless in assembly and function out of the box. Jim sells a brass Queen Ann lock and I've discussed adapting that lock to the swivel breech with Dave Waters.
Lots of irons in the fire here, I machine aircraft parts in my shop and that keeps me very busy with first article inspections, monumental paper work, metal certifications, certificates of compliance and so on. I'm a little short on time now.
Cheers,
Tony