I bought a 1-4 24 scope for my AR. Says that it's a 30 mm tube. So I bought a mount that says it's for 30 mm tubes. But its to small. Won't fit in it.

I'm confused as to why not. This is my first variable scope.

So I obviously did something wrong. Or something is wrong on the mount or scope labeling.

Scopes a vortex crossfire II.
Looking for help.