Five-year bump for Jon, since he just asked me about this via PM, and I never replied to this originally, lol.
Full disclosure, this is hard to explain. And I take no responsibility if you break anything.
hold the empty shell as it is oriented in the game (i.e., trigger at the top and away from you), grab the bottom two halves (after you remove the screw of course, and the trigger parts, which I think will fall out if you spread the halves partway, that part I don't remember as it's been so long since I had a full stick apart).
Apply GENTLE spreading pressure from the bottom, then
slightly push the right half (in your right hand) away from you, while pulling the left half toward you. Then wiggle the two halves gently back and forth while keeping the spreading pressure as consistent as you can until they pop apart. (And make sure the spreading pressure is less than the amount that will crack the plastic, lol.) Note that when they do pop, it will still sound like something cracked, even if nothing did. So don't be alarmed if it sounds like something broke (unless something actually did, in which case it still won't be that bad, keep reading.)
The wiggling is important, as it will help 'walk' the barbed tabs to the point where they'll disengage. The number of times you have to wiggle them will vary depending on how worn the tabs are, but you'll need to wiggle it more than you think, like 15-20 wiggles at least, again while applying GENTLE spreading pressure. Better to err to the safe side, worst case is you'll wiggle them 50 times and they still won't come apart. Slow and steady is part of the trick. If you push it too hard, you'll crack or break one of the tabs, usually the one closest to you.
The good news is that even if that happens, the other tab (closer to the trigger side of the stick) will most likely still be ok (as it receives less of the stress), and that one will still be sufficient to hold the halves back together tightly when you reassemble. I have three spare used shells for these, and two of them have broken or cracked outer tabs, but the inner ones are still ok. And they still snap back together fine.
Here are some pics of what the tabs look like, to help you visualize.
Clear as mud? Good.
