I've recently had my gas tube lever on my AK come completely off after shooting it at the range. I haven't lost it or anything, it just doesn't function anymore.

I've done nothing out of the ordinary with my rifle to cause this either, I've only used it as intended. No unnecessary beatings, mistreatment, or anything like that. The lever has always been on the loose side since the day I picked it up new, now it is able to come completely out of the rifle. It still functions though, it hasn't had any cycling issues while using it with the lever completely removed because the piston doesn't pull back far enough to cause the gas tube to fall out or anything. I've read that you can "easily" fix this issue by taking a brass-pinging hammer to the levers open face and kinda mushroom it out again to make it fit snug. Supposedly this should work, well not for me. I've only succeeded in putting dents into the hammer and the lever is just as loose. Maybe I'm not whacking it hard enough with the hammer to have a good effect, but it really doesn't sit right with me to just pound on the rear-sight block with a brass-hammer.

I haven't done anything too extreme, the finish still looks good on my AK. I put a cloth over before I started tapping, then hitting it with the hammer... I don't want to cause anymore issues than I already have, so for right now I'm just living with it. But still kinda irks at me, has to be a better fix for this than just whacking it like an ape... Or maybe not, figure I can post here for help.

I do plan on buying the Ultimak gas tube rail for my AK eventually, which is ringed onto the barrel directly so it wont move. Obviously this would prevent the tube from going anywhere, but still not an ideal solution for the above problem.

Other than the brass hammer not much else you can do besides maybe call the dealer you got the rifle from. If you do it right you shouldn't be touching the rear sight block at all, just the end of the pin.