Well, as this is a rabbit trail I think I caused, I guess I better comment.
I think Bryce, the point you're making here is this: A high degree of under-boring is a know cause of aberrant accuracy, and this aberration is present in the test you just completed with the somewhat poor marbs. Therefore, paint grade doesn't actually obscure barrel-induced effects.
I agree to a point. A high degree of under-bore will add obscene amounts of spin to the paintballs...this is the cause of the increased shot spread, of course. From my own testing, these are the conclusions i have come to regarding shot spread:
The two largest forces affecting shot spread are paintball surface-induced asymmetric boundary layer separation, and spin-induced asymmetric boundary layer separation. These two forces both act on the balls during flight to the target, but the total increase in shot spread isn't an aggregate of the two forces
. They interact in a more complex way. The surface-induced forces are generally much larger than spin-induced forces (excepting very high rates of spin), and lower rates of spin-induced forces CAN be almost "absorbed" (for lack of a better word) into the surface-induced forces. I noted this during my short obsession with patching paint. Patched paint from a smooth-bore only shoots tighter groups if the paint is free of surface imperfections. Poorer paint will shoot similar groupings whether patched or not. I have also documented (controversially
) incremental increases in shot spread correlating to bore size that Punkworks hasn't replicated in your own testing. Perhaps it's my obsession with using only the best performing paint I can obtain, idk.
Anyway, these differences aren't apparent with anything other than high performing paintballs. What do I mean by high performing? I've shot dozens of tests myself, and I have a benchmark that I apply to the paint I use. I have to be able to shoot a 5" vector at 80' with it for me to bother completing a test with it. Tests are a lot of work and I just don't want to loose any possible subtle results. I'm a bit obsessive that way. I don't have a lot of 100' data, but I'd guess that good paint should shoot a vector of no more than 7"-9" at that distance. There's considerable "noise" to sift out if your paint is delivering 14" vectors.
Nevertheless, the possible muzzle effects that the new barrel was designed to mitigate are much subtler than the surface-induced forces poor paint can generate. Why not eliminate as much noise as you can?