Ummmm... the ONLY place lube should be is INSIDE YOUR GEARBOX
You want your hopup unit, nub, bucking, barrel, nozzle all to be completely dry. Take your gun back down and take the inner barrel and bucking and wash them in warm water with a tiny bit of dawn, let them air dry. Put it all back together.
Sorry to bust your cap, busta_cap, but not so. I've worked as an airsoft technician for a living for 4 years, and every barrel and hop-up rubber needs to be lightly lubricated with 100% silicon grease. Three reasons:
-Rubber bucking will dry and crack if it is not properly maintained with a lubricant
-Air nozzle needs to have a good seal with the hop up rubber, which isn't possible without lubrication
-BBs traveling down a smooth barrel need as little friction as possible to maintain consistency and muzzle velocity, so the barrel needs lubrication as well.
Sorry dude, you're wrong. 
-BATMAN
Uhh, Nope. The Nozzle should meet the hopup chamber at tight tolerances, but you would need quite a bit of GREASE to actually maintain a steady seal if there was that much of a gap, and then grease is going to go flying into your bucking and barrel. This is why having a properly fitted nozzle and bucking with the proper taper is important.
BB's are typically 5.95mm and SHOULD be within a .01mm tolerance as well as highly polished. Inner barrels that have the best consistencies are the tighest tolerance without interferance, as well as having the most consistent tolerance down the barrel. The BB is meant the actually fly down the barrel riding on a constant cushion of air around the bb and behind it, not slide along the barrel..If you use lubrication inside your barrel and hopup it will actually create fliers and inconsistencies due to a few reasons explained in the following diagram. It's simple physics.
As Far as the hopup rubber goes, if you use a quality rubber it should not crack. Maybe over tens of thousands of rounds. Also, hopup rubbers are not meant to last forever. The problem with adding silicon is, again, you can never coat it perfectly, the surface of the rubber would come precoated if that was the case.
If you don't believe me, with all your vast knowledge, I can certainly refer you to some people who have pushed little plastic balls passed the limits of what most people dream of, Clarence Lai the Co founder of Redwolf Airsoft and Airsoft Surgeon, Or Mike Of Righthook Fabrication, or Ben Satori of Satori industries, Troy Kim of 2roy. I doubt any of these people will tell you to lube your hopup rubber on the inside, nor the barrel.
If you plan to have a rebuttle to this post, please atleast provide me with some data or theory behind your statements. Shellackin' lube inside your hopup and barrel just won't cut it.
