Hey, I got my first 510 joye kit this week. All is well, very much enjoy it. The cartridges I have came with it, and don't really snap in. They slide in but that's it. Seems a bit fragile to carry in your pocket. I have an ego-t due for delivery next week and recall watching a video about pushing it in till it clicked. Wondering if it's just the type of cartridge I have for the 510? Thoughts?