Donaldo.
Don't know what a tapered thread is. But one thread that could be used is an Acme thread. If you have seen a screw in choke by Brily the ones he put into those thin barreled SxS. These are square threads and very shallow about .002" deep. A 1/10" sleave would leave enough meat. These threads only need to withstand the back thrust the cartridge.
You figure it out, how many threads you need 2 thou deep to keep 4-5 tons in place. Using the compressive strength of soft barrel steel. This would have to be done on a precision lath with no plus or minuses.
Hey, we are talking mula again. Not consistent with the Handi clan.
If you call Brily they would tell you if you can get enough threads into 4" to hold the 10K.lbs back thrust.
I am simply too tired to do calculations like that anymore. A mechanical engineer with design programs could do it in jiffy.
The Brily threads are very close fitted and the changing of chokes takes forever, These chokes are made from some tough material they are super thin. They are a work of art and they don't blow the end of the barrels off like some did.
Next time I go to my friends machine shop I will ask him.
I think this Brily thread and choke is patented?
The inside threading tool is another hunk of mula. Besides how many customers would share the cost. This is nothing but a pipe dream.
Nice to talk about but that is just about it.
Just rebore a Handy that is the only reasonable way to go. The 24" 223 bull barrel wil do any thing the Handi can handle. On top of that you gat a fine bore and chamber. I am really pleased with that 257 Roberts.