If it's an American Vintage Jag, you just gotta push it in REAL hard. If it's the first time you've done it, you'll have to push a lot harder than you'd think, it snaps in after applying significant pressure. It's also hard to get out the first time, too, I had to pull even harder to get it out than to put it in. After a few times it gets a bit easier. If it a Japan model, I think it's the same procedure, but haven't had any first had experience with it. Good Luck!
