Comparing between a VSR with 1J setup and TK, and an M16 with 1J setup and TK, the difference is just as big in terms of range differential as there is between an upgraded M16 at 400 fps and an upgraded sniper rifle at 550. The inconsistency of the AEG really hurts how well it can perform with the TK.
Besides, a VSR with a 1J setup has a very light bolt pull, and, especially if you're using the GSPEC, it's going to be deadly quiet, and accurate out nearly as far as a normal upgraded sniper rifle.
Sure maybe an M16 will be more effective at getting kills than a sniper rifle will--if you play as a rifleman. If you're playing as a sniper, which, judging from the section, the VSR will ALWAYS be better. Airsoft sniping isn't all about how many kills you can get. Nor is it about whether you can compensate for lack of an accurate weapon and lack of skill with ROF and more ammo. Your comment is spoken like a collector, not a skirmisher.
More, it's also spoken like someone who's never even USED a setup like the one I described. I have. I was actually more effective that game in context of kills than I usually am with my 550 fps rifle. Quieter gun, nearly 220 feet of effective range, easy bolt pull for great ROF... It's a great sniper setup.
And boreup doesn't mean squat, especially not for a VSR. You can run a 555mm on the stock cylinder, which has far too much volume anyways. I think you're making the mistake of confusing the effects of better tech skill for the effects of the bore-up. I've upgraded guns with boreup for people before. It doesn't inherently increase accuracy, nor is a 400 fps setup using a long barrel and boreup more effective than a normal upgraded rifle at 550 (or even at 400).
Besides, longer barrels than 450-555 are WORSE in airsoft, because they're less concealable, and they give your position away, and can get stuck on things, and do not offer much in the way of accuracy advantage. That's why I don't skirmish my SVD--it's huge, it's far too long, and it's loud. PSG-1 barrels in a VSR are worse than useless. It is very very rare to see someone use a rifle that long effectively in a game. I love my long guns, but there's a point at which it becomes absurd and detrimental.