Mossberg with red dot cut out ?

[nyhunter]

I have a Mossberg 20ga with the cut out on the back of the receiver for a red dot. it came with a Holosun 407k " I believe " on it, I'm looking to put a different red dot on it has anyone changed out the red dot and if so what did you put on it? The main reason I don't like the Holosun is has a huge 6moa dot on it and I want something in the 3moa-4moa range .

Thank you Gerri