In theory this sounds like it should produce better performance. I will try it out myself with brass and PETG this weekend, but is there anyone out there that has tried this type of barrel, and could shed some light onto if and how much it increases performance?
I have tried this with 3" of CPVC and 13" of Sch.80 and it worked well. The barrel significantly decreased the problem of darts fishtailing out of a 14" CPVC barrel on my pumpsnap and new latex-double SNAP design, making the dart fly much more accurate than normal CPVC. I am not sure however, if it increases range too much, if so, only 10ish more feet. Also, I see no flex in my hopper other than the usual, but it does add weight, occasionally falling out.