Dumfries and Galloway Police detained the farmer 22 hours after receiving the allegation and allowed him to retrieve his guns himself for seizure, the Police Investigations & Review Commissioner (PIRC) heard.
A farmer accused of wielding a loaded gun "ought to have raised a concern that he might present a danger" and should have prompted an immediate response, said Commissioner John McNeill.
On the evening of January 22 2010, the farmer reported poachers on his land to police after having seen men with hares or rabbits.
When an initial police search proved fruitless the farmer went out alone with a shotgun. But police did not detain the farmer until around 8.45pm the following night.