Just be careful if you wrap the hop rubber in PTFE tape.
1. use silicone grease on the outside once wrapped (or CT-2 Teflon(PTFE) Silicone grease for best results*)
2. if you have to press very hard to make the barrel with rubber fitted slide into the hop unit, you risk the rubber jamming and the barrel pushing through inside it, which can damage the rubber.
Ideally the barrel would have been cleaned with a spotless soft cloth using soapy water, rinsed thoroughly with water, air dried, and finally cleaned again with an alcohol swab, to remove every last trace of oil, grease, or muck, both inside and where the rubber fits outside as well. Once the alcohol has evaporated, using freshly washed hands, when you carefully fit a new rubber onto the barrel, there will be the maximum amount of friction between the two, which means that when it comes to wrapping the PTFE tape around the rubber, you will be able to use a fraction more (which when greased with CT-2 will still fit), resulting in the tightest air seal and most stable breach-end.
In practice, the only area that you need to keep relatively grease free is the bump inside the rubber and a good slap of grease will get you past a multitude of sins. You can always give the barrel and hop a clean from inside with alcohol swabs later.
AEG accuracy itself is always going to be more at the mercy of air movement than almost anything you can do anything about, but also, due to the way that AEG's are usually fired in skirmish, body movement. Are you sufficiently well practiced that, while moving under fire, you can bring your AEG up from a muzzle down carry position to your shoulder in a fluid movement which ends simultaneously with your dominant eye aiming over iron sights to a man sized target 35m away and with a trigger pull which puts a hit on that man sized target first time and pretty much every time (ie with no need to correct your aim before pulling the trigger, and no need to correct for wind unless conditions are blustery)? If you can then there may be something to be gained by homemade improvements, but first try an H-nub, a sticky hop rubber combined with heavier BB's, and a TBB.
I would suggest that, unless your inner barrel is so loose that you can hear or see it wobble, there is so little to be potentially gained by fucking about with tape that dismantling your gun just to do it is asking for trouble. In some ways AEG's are pretty simple mechanisms, but the trouble is that the parts are manufactured within varying degrees of tolerance, which means that any particular gun which works, as it is, can go back together seemingly just as it was and not work, apparently for no earthly reason. Naturally you can just re-dismantle it and re-reassemble and often that will do the trick, but trust me, the more you fuck with it, the more likely it is that you will fuck something up...
*CT-2 is brilliant grease for every part of any airsoft gun - it is without question the way forward.
