This question already has an answer here:
The human colony has been on this planet for some time now and are hearing that more ships from Earth are on their way. They also have developed a weapon that puts a pretty good sized crater on the moon. The ship that's on its way is described as having to have drugs and graft and other unsavory parts of humanity on it just to allow the people to be able to 'live'. The colonists are not happy about it, for they have developed a little more utopiany way of life.
The story is 3rd person and 1st person story telling. Radio transmission tells of ships coming (actual space trip takes years), towards the end I think a young boy figures out the secret weapon (that puts crater on the moon).
I remember one moment in it where the natives are in a bar (they all generally pack pistols due to all the animals in the area) and one of the newcomers is hassling a woman and she says NO to him twice during his advances as he's a bit drunk and fresh off the ship, well before the third NO some native in the bar shoots him dead which is how they handle things, not necessarily violently but directly and finally.
I read this in the eighties and it seemed old to me at the time, paperback