Matthias
good to hear something from you.. I was worried about you since I can't remember last when we talked..
so I assume that everyone has their own way of doing it, but from my experience, especially if you don't know if you actually have a choked barrel would be to pull the barrel and go from the breach end.. you likely can just use your cleaning rod and if you are very careful, I have been actually able to measure twist rate with a cleaning swab.. just a mark on the cleaning rod and then watch for a complete revolution and then measure the distance traveled..
you will want to remove a moderator if installed because who knows where the slug will end up.. if you are not sure if it's a choked barrel.. then you can always push the first one through all the way and if it gets tighter when you get to the muzzle, then it's choked and that would give you the choke diameter..
then only go part way in and then push it back out with the cleaning rod and that's the regular bore..
now something came to mind when you were describing the calipers, you possibly have duplicating calipers? I have a few old ones that are basically not able to measure, because they don't have markings.. they are just useful for comparison..
I have all, so just a simple caliper with a dial indicator for down to 0.001 increments, I also have a cheap digital caliper from harbor freight.. China that seems good as any, especially for $25.. then since I do have said lathe and mill, I have a set of micrometers.. 0-6".. I rarely use those as for everything I do currently the digital caliper is good enough.. but I'd be worried about you using the micrometers because they have a spring loaded wheel so you tighten them down basically like a c clamp and the spring loaded wheel makes sure you tighten the same amount..
myself I would use pellets for slugging and no need to hammer them larger.. hopefully they already are and you will be able to easily see the lands and groove.. also they should be a lot easier to push than a tight slug.. now the issue is if you use pellets and they are hollow like most are.. I'm afraid of the micrometers tighten too much and getting bad reading because it crushed in instead of just measuring..
you can always try pushing in from the muzzle if you want to try to avoid pulling the barrel.. just remember if you start out tight and then it gets loose all the way to the breach.. then you have only the choke diameter..
I also assume that choke diameter is important because if it is a tight fit in the chamber or bore, slugs being solid might get stuck in the choke..
so hopefully between everyone you have a good idea of how to accomplish what you want.. please don't hesitate to ask any questions..
yes there those of us who have had experience with most things including machine shop.. but it doesn't make you less smart.. your just starting where we did, no knowledge of it.. and I personally can tell you if it was not for a friend who was a mechanic, welder and machinest.. I wouldn't have half the knowledge I have.. he actually took the time to show me how to do things and learn..
that's a valuable experience.. and while we might not be able to show you hands on, but I expect with the YouTube video and others you can easily learn this..
so if you don't understand anything please ask..
I don't always find these threads again.. yes I could use both help with computer and Internet and also memory for the next day
it's good to see you around..
also I seem to have disappearing pm messages, so you can just start a new pm if you want to ask me anything..
one more thing.. id use blue locktite for the setscrew on the barrel.. red locktite is too permanent.. I prefer to apply it to the outside thread of the setscrew and then put in.. I also have it in a, well like lipstick tube.. that one is really handy since it doesn't run, doesn't dry out in the tube and doesn't spill..
that kind that was mentioned above that seeps into the thread sounds interesting, I am going to have to check it out, my only concern is if it hardened up in the head of the screw, might be a issue for disassemble next time
Mark Hooper