[ThunderCactus]

With my prometheus 6.03 in my VSR-10 I noticed accuracy loss due to fouling after just 120 rounds. However slight, fouling can occur very quickly, especially in AEG's where you're constantly spraying grease particles into the barrel and potentially oil from oiling your mag (that's why I say not to do it)

With my PTW I noticed the same thing, the widebores definitely negate a bit of the problem. Doesn't take many rounds to start to drop off in accuracy, but I wonder how many people actually notice?
And take into account LMG's that go through 2000-10,000 BB's in a game. If accuracy loss occurs at 120, 500, or 1000 rounds, they're still suffering from it. So the best option for sure is a wider bore 6.08-6.13 (still not convinced 6.10+ is a real benefit)

If the BB was riding the top of the barrel I'd expect there would be a contact line there, especially in heavily used barrels like my 249's. Regardless of whether the backspin is matching the fps at the beginning of travel, it won't be the same by the time the BB leaves the barrel as it's continuously accelerating and there isn't sufficient grip in the bore to further accelerate the backspin, creating friction and thus a contact line, right?

I do agree we have no idea what the maximum potential of a 6mm spheroid is though
We also contend with the fact we need to retain certain velocity. With the R-hop and ER-hop you can use heavier ammo than would normally be possible with some range and accuracy advantage, but unfortunately the reduces relative fps makes them much easier to dodge. So at 1.6j with an ER-hop let's say for example a .43g would net the best range and accuracy overall, it may not be ideal since it's going so damn slow.