Long story short, I screwed up the barrel lock on my stainless Chinese cage last week, so we reverted to the polycarbonate Mancage device. That damn thing nearly chewed my balls off in a few hours. I wouldn’t recommend their products to anyone. I may give it one more try, with the largest ring and less gap, but not right away. My replacement barrel lock arrived yesterday!
I’m gifted that way I had been fighting sharp edges on the exposed areas of the lock. They would dig in while sitting. So I filed the offending areas to round off the edges. No problem other than the little pointy protruding area next to the moving lock part. I decided to take the Dremel and remove it. So far so good. Of course in my mind, if a little bit is good, a little more is better. So I decided to cut down the top area that stuck out above the cage and ring. I had not considered the fact that the springs and tumblers reside in that area. Yep, functional parts and pieces went flying!. It would then turn with or without the key. My Queen then decided I needed to be locked up in the plastic contraption for my foolishness. As it quickly became too much to bear, we switched back to the stainless cage, using a bandaid to secure the lock. $8 later Amazon had a replacement on the way, which arrived yesterday, a day earlier then expected.
I have softened all the edges on my barrel because, like you, it's on a metal cage so it's exposed at the top (unlike with plastic/resin cages). Fortunately, I guess I knew when to stop, lol.