The club’s walls were covered with threats in red paint, one of them reading: “murder, meat eaters, we will be back”.
Chairs and other furniture were also smashed and other items damaged.
Association president Ron Bryant said the act was an example of “disgusting filth” that showed a “militant-type behaviour”.
“All shooters are tarred with the same brush. It’s an ongoing vilification that we suffer,” he said.
The vandals entered the property on a motorbike and broke into the complex sometime between 3pm on Sunday and 8am on Monday.
The Association has more than 160,000 members, with many taking to Facebook to express their outrage.
One user said: “Murder is classed as a crime., (but) vandalism is also a crime and so is unlawful entry to a premise.”
In 1990, WA banned recreational duck shooting and hunting is now limited to feral and pests on private property. Shooters must have the landowner’s permission and a current license.
“It’s purely a target shooting club, it is paper targets and no hunts occur,” Mr Bryant said.
“That club is home to many Australian and international champions, … shooters that have been there for years and gone to the highest level of competition, not only in Australia but throughout the world.”
Mr Bryant said the club was also damaged during a break-in about six months ago.
The club’s security system has already been updated and the other 70 shooting clubs in WA have been advised to upgrade their security.
“Yes, we have hunters, yes, we are target shooters and, yes, we are collectors. We are firearms enthusiasts at the end of the day,” Mr Bryant said.
Anyone with any information is asked to contact Crime Stoppers on 1800 333 000.