If you just want to be able to force the battery pack out by pushing from the head end, that should be doable. But if you want to pull the switch out the head end so you can force the battery pack out the head end, that could present some problems.
For either method, you'll need to loosen the switch so it can move. First remove the rubber switch cover, it just prys off. Then insert the long end of a 5/64" (or 2mm) allen wrench and insert it into the allen screw that's way at the bottom of the hole. Loosen the screw until it is free spinning. You also want to have the button pushed all the way in so it doesn't catch on the edge of the switch hole once the switch starts moving. Be careful, the switch post can extend itself if you turn the switch upside down.
If you are trying to push the battery holder out the bottom, you can push on the top of the switch and push both the switch and the battery holder out. You will want to push on the top of the switch itself, not the bulb post, to prevent/minimize any possible damage. I found that a piece of 3/4 PVC pipe will fit around the bulb post but still be small enough to fit inside the snap ring, which will stay in place. But a deep well socket might work too. Just put one end of the PVC on top of the switch and whack on the other end to force out the switch and battery holder. You might damage the 4 little plastic "braces" at the bottom of the bulb post but they aren't important. You should be able to whack pretty hard without damaging the switch itself.
If for some reason you need to push everything out the front, that might be close to impossible. The problem is trying to remove the snap ring. There is a groove in the top of the switch that rests against the snap ring. With the switch still in place, it will be close to impossible to pry the snap ring out of it's groove in the body. But if you're going to try, the best method is to pry one end of the ring out of the groove and slowly work your way around to the other end. When the switch is removed, it's easy because you can pry out and push down at the same time and it will pop right out. With the switch in place, you'll have to try to pry it out and pull up to get it out. Personally, the couple times I've tried this way I've given up and just gone back to forcing everything out the tail end even if it destroys things.
