When you get the chamber/inner out of the outer barrel...turn the hopup all the way off. Look down it from the chamber in and note how much of the rubber nub is sticking down into the barrel. I will guess:
1. It's crooked...there's seems to be some retard at the factory who just slaps the rubber on and doesn't bother to make sure the nub is fully pushed through the hole. To fix that you'll need to get it taken down to just the inner and hopup rubber...pop the rubber off to check for permanent damage (a little memory dent of its misplacement is ok and will wear out)...then put it back in properly (then check #2).
2. It's sticking really quite a bit into the barrel. Too much. Basically I buff/sand the nub down until I can just see a bit of it when the hopup is off (guessing taking off a bit more than half of what you can see pre-mod). (take it apart...flip the ring inside out and put it back on...that'll position the nub nicely...buff the nub off evenly with 400/600grit emery paper, maybe a bit coarser to start...check often). At that point you'll probably have too little hop for 0.30's...but finer hopup adjustment. So...I use a little circle punch I made on the lathe to punch out discs from shrinkwrap material (seems to be a nice combo of thin enough and stiff enough). When reassembling it I drop a "shim" or two of the material down the hole, then the BB, then put the rest of it back together.
Doing the above you'll still see some nub when the hopup is off...but not nearly as much. The sharp corners of the nub will be gone too (which is part of what I think leads to the hooking). As you adjust the hopup on, you might not see a whole lot move down into the barrel (you'll see some), but it'll be progressively stiffer since there isn't as much rubber nub to be "squishy". It'll have a bit of a rougher surface too (molded vs. 600grit finish)...so you'll probably see the action even out after a number of rounds through it.
Hope that helps guys...like I said...if you're skittish about doing your own, buy an extra hopup rubber first...or get the Stinger hopup (it's basically premolded the same way with much less of a bump and plastic/paper shims).