330 is too small to maximize efficiency on a tac-41. You should be going 430mm minimum, probably higher.
The main issue is FPS. A short barrel will not utililize the tac-41s large cylinder, so lots of extra air will get blown out. I'm not sure whats ideal though. My calculations show that for the most efficient barrel setup, you should pick a 420mm for .48g bbs. It's the perfect barrel ratio for .48g bbs.Hey Sodium, good to know! Would there be much if any gain in distance by opting for a 510 over the 420mm barrel?