Doesn't hold up well to repeated shocks & isn't the solutionj to your problem. It will however, last for awhile.
Page 1, 4th post down shows pics of the handle retaining detent. You probably have some crud in the detent channel. You can use brake cleaner to hose the channel out, and a punch to move the detent (to make sure it moves freely).viewtopic.php?f=7&t=244200
Replace the handle, and pull- it should take a bit of effort. if it is still not engaging, you can use a needle round-file to deepen the notch in the handle, and/or replace the detent spring. An AK47 disconnector spring, slightly trimmed is a perfect fit, BTW.