Yes, my results are based on Pyrodex and Goex, wonderwads, good tight .018" prelubed pillow ticking, and Hornady/Speer balls...I've accumulated a number of used TC 1:48's over all the years in .45/.50/.54cals, both caplock & flintlock, and the results are the same.
I scrub them down to the bare raw metal like they left the factory, I use Shooter's Choice Black Powder Cleaning Gel to dissolve any tar buildup...then nothing but steaming hot soapy water and natural lube 1000 go in the bores after that...not a dog in the bunch...they span all the various vintages of barrels from the 70's/80's/90's up to 1995...old ones without crowns, newer ones with crowns, some with old style sights, some with new style sights, etc...I don't happen to like the QLA feature in barrels made since 1995 so I have no 1:48" barrels made after that date.
I did have one TC barrel problem...it was a brand new .50cal x 1:66" round ball Flint barrel who's POI would begin moving way off to the left as it heated up...wasn't enough rear sight adjustment to contain it...if I let it cool off it would print back to the right...TC replaced it.
Years ago I decided to switch to PRB's, and based upon hearing that 1:48" barrels were not accurate with PRB's I started out with a .50cal RB barrel, then added a .45, then a .54, etc. Years later, as I needed reasons to keep doing something new on my Saturday morning range trips, I decided to start running side by side test comparisons between my 1:66" and 1:48" TC barrels for each caliber.
Each Saturday I tested a different caliber using my same full power 1:66" hunting loads in both twists:
90grns Goex 3F
Wonderwad
.018" prelubed pillow ticking
Hornady .440/.490/.530 balls
Identical loading procedures, identical cleaning & lubing procedures, identical weather & range conditions, etc...5 shots with one, then 5 shots with the other so no one barrel would heat up excessively...they all printed in the 2"-3" range at 100yds and if someone had shuffled the targets together and handed them back to me I would have had to pause and study a little to try and pick out the 1:66" targets from the 1:48"...same results with percussion barrels.
Maybe the different experiences are matters of degree between people's expectations...for me I'm tickled to death to shoot a group smaller than 3" at 100yds using iron sights and 60 year old eyes and I call that excellent accuracy...others may scoff at that and only accept 1" groups at 100yds as being excellent...but at any rate, the above tests and weekly trips to the range year round are the basis for my statement that TC's 1:48" barrels produce excellent round ball accuracy.
In fact, I've often said if I could only have one TC Hawken barrel, it would be a .45cal X 1:48"...the 128grn Hornady balls and 255grn TC maxi-hunters just eat the bullseyes out of targets and would give a lot of small & large game versatility, economy for plinking cans on the weekends, etc.