A silenced, semi-automatic rifle has allegedly been uncovered during a drug raid in the state's south-west.
Officers carried out an initial search warrant at a Withers property last month, following a 6 month effort to collect information as part of Operation Zagros.
Detectives allegedly uncovered more than 150 grams of meth at the property along with a weapon and more than $20,000 in cash.
A 43 year old man has since been charged with six offences including possession of drugs and a weapon.
Yesterday officers from across the South West District carried out another 14 search warrants in Manjimup, where a further 12 people were arrested.
They've since been charged with a total of 58 offences.
Among them was a 45 year old man who is facing charges including 19 counts of offering to supply meth, along with the alleged possession of other drugs and cash.
Another man, a 37 year old from Manjimup is facing three counts of selling meth and one count of possessing cannabis.