When I was new to competitive shooting with ML's, the military was still buying pillows made with mil spec. ticking.
I was using that with moosemilk. Back then I was shooting a lot with my late friend Bruce Scwuindt. He taught me the ins and outs of cross-sticks shooting.
We were doing just that one day. We were at 50 yards that day . I was shooting a GMT barreled TC Hawkins. I was shooting pretty good groups, so I thought.
Bruce came over and gave me a strip of .018 Teflon coated Texas patching and told me to shoot another five shots with it. He said I needed to wipe after every shot with it. He also told me not to look at my target till I was done with the five shots.
I went ahead and shot five shots with the Texas patching, and we called a cease fire, and I was quite surprised that my group was half the size of what I was shooting with ticking and moosemilk.
Needless to say, I started using the Teflon coated patching with all my rifles.
I did very well with them. I never had any problems with it building up in the barrel.
I used the teflon coated patching until I got a Rice .50 caliber barrel with round bottom rifling.
Cleaning between shots would foul up the breech so bad I had to scrape it after five shots. The barrel still shot very well but this was a real peta.
About the same time the guy that was making Texas patching died. I still wanted to use Teflon for my crossticks rifle and what became available I did not like.
I experimented with different types of patching and found some guns like pocket drill lubed with bear oil, and some like denim and some others like canvas. However, my chunk gun with a 1 and 1/8-inch Douglas barrel shoots significantly better with .020 Teflon coated patching than with anything else I have tried.
I don't know about empirical data, but serious target shooters in most disciplines use Teflon coated patches.