I brought my Browning 12 pump with a 30" barrel and was told by my dad and another guy that it's not a good idea.... why? I took their advice and shot one dove
You ask this question then are a bit of an a-hole.
I don't know why your pops told you that, you can shoot whatever you want, but was it a choke issue?
It has zero to do with it being a pump or the barrel length, if it does your Dad and other fellow are just as clueless. There is some argument for shorter barrels being easier to swing, but it aint like a 30 inch barrel pump cant be a dove killing machine.
Basically your question is not answerable because it makes zero sense. Sounds basically like two guys with little knowledge talking to another.