‘Operation Porthos ran for a period of six months, targeting the trafficking of firearms and drugs,’ Clarkson Detectives Senior Sergeant Gary Saunders said.
‘Targets of the operation had outlaw motorcycle club links.’
Sgt Saunders said detectives searched several properties in the north west metropolitan district and found 28 firearms, including 10 handguns, 13 rifles, three shotguns and two machine guns.
He said police also found more than 10,000 rounds of ammunition, including armour piercing rounds.
Sgt Saunders said they found more than 1kg of methamphetamine, about 40g of heroin and more than 200g of ecstasy during the operation.
WA Police launched a firearms amnesty on August 1 for people with unlicensed guns to hand them in with immunity if they had not been used in an offence.
A spokeswoman said of the 166 firearms handed in during the first three weeks, 17 had been handed in across the north-west metropolitan district.
For more details on the amnesty, call 1300 171 011, email email@example.com, attend a police station or visit www.police.wa.gov.au.