I know that some have faulted your efforts on this thread. I admire your skills. Most locks made in India - and many made in Spain, Italy, or even the U.S.A. - need some work. But I'm starting to wonder if you'll end up like the guy in that old story with the genuine antique Native American tomahawk which had three new handles over the years and had the head replaced once. But he still cherished it.
i posted a question here about purchasing a blunder buss made in india and the answer i got was they were pretty good now i read this and am glad i didnt buy one. ( i still need a blunderbuss but just havent felt i could spend the money till the china virus gets under control ) i cant figure how they are good one month and then bad the next. i know there are always quality problems but sounds like india is not the country to buy from.
Only cons, in my oh-so humble opinion.
I am a metallurgist who as a side-line (sort of) was Expert Witness (for the plaintiff) in a few muzzle loading lawsuits.. The first I looked at was a guy who loaded his brass-barreled Indian blunderbuss with a large blank load of black powder with newspaper rammed down on top.
The breech-plug blew out. Lord Be Praised! It missed his head. Can't say what condition his shorts may have been.
The fine breech threads were just a little bit smeared over at the tips. Don't recall whether I could screw the thing back in, but it sure was a loose fit. You follow me? That plug was such a loose fit that it blew out without damaging the threads.
This is what you can get with Indian work. Absolutely Zero understanding of what they are doing.
This back in the 1980's. Have they improved since then? Would you bet your body parts on this?
Buy a barrel from one of the American makers. Fit it to an Indian gun if that suits your fancy. Then destroy that Indian barrel so no one can get hurt by it.
By the way - it is well known amongst competent machinists/designers that one never uses fine threads when working with brass. Only coarse threads. If your barrel maker disagrees, bid him a pleasant goodbye.
I've spent a lot of my adult life designing/building custom CNC machines (mostly laser and waterjet), and I am impressed with the ingenuity and skill of the OP in turning a poorly built lock into a functioning tool. It has been an educational experience, and for me, it's ranks up there with a 1st rate machinist or TIG welder. Thank you for sharing.