__note that I started this reply before the last several posts were up__
Do you guys think I should ring TVM to change to square bottom rifling?
I think you should quit trying to build a gun by committee and let TVM get on with building the gun. What if they have already ordered your barrel and you end up sticking them with one they will have to keep in stock until someone else requests one. Gunmakers hate those who waffle during the process.
Asking for "opinions" is not a subjective way to get facts. You only get personal preferences. It's kind like the current political situation.
As a professor of mine used to say about the law:
You pays your money and you takes your chances. I agree with Dave here to the effect of if you keep pecking at your TVM order, you're sure to get something those fellows are sick of and just want it out of the shop. Don't do that to decent gun-making folks or to yourself (it may land your gun on the "special needs" category delaying delivery). Pays your money and takes your chances.
Just never forget that no matter what ball or patch or bore or rifling or steel or lube or powder/prime or flint/cap your lock and trigger you gun winds up being constructed with, YOU yet have to develop a load for it. And
your load won't be exactly the same as anyone else's.
Unless you
copy cat someone else's load and "hope" it works. It might work if you can get it down the bore, or it could fall in. But it won't be optimized for accuracy and best performance available from your gun. Loading procedures tend to be different, lubes tend to be different, patches, etc. are different, as are the machining tolerances that allow some variation between moulds and bores actual sizes when measured past their nominal designations.
It's too easy to "think something to death" and come up with
conclusions in theory that do not work, or do no work well in application. But it's great to learn of the most common options and variations and opinions in practice. That way if process X doesn't work as you thought it might, you can jump right to Y and see how you like that. It should come together in a way similar to others, but not quite exactly.
Just don't get your mind
all made up before you're ramming balls and looking for patches and making holes in paper.
Hanshi hits the bottom line here:
I use thick unbleached canvas and it fills out the deep rb grooves completely. Actually, it's just a matter of finding the load your barrel likes.
There are a lot of paths to finding those loads your bbl likes, and you can't do it online, but that's what has to happen for best satisfaction of any shooter who cares to land their bullets near the x.
I spent too many hours developing loads for moderns in order to extract best safe accuracy, it's actually somewhat simpler with BP. But so much more fun. So do that. Have fun, and trust your maker.
You can always choose another maker for your next one, after you know much more about what you want.
