More than 30 officers from Operation Airborne who raided an illegal waste operator in Reading found a loaded gun, £45,000 in cash and a safe.
The haul was discovered on September 10 during the joint operation by the Environment Agency (EA), the Regional Asset Recovery Team and Thames Valley Police. Operation leaders had suspected long-term illegal waste activities were taking place at the site.
Hugh ODonnell, 60, from Paices Hill, Aldermaston and Thomas Boyle, 43, from Andrews Close, Theale have been charged with firearms offences and were due to appear in Reading Magistrates on September 12. A 49 year-old and 50 year-old from Hampshire have both been released on bail to return to Loddon Valley Police Station on November 3.
PC Ian Henderson who took part in the operation said: The illegal dumping of waste is a serious crime and those involved in such activity will be dealt with accordingly.
An EA spokeswoman added: Waste crime is now another method of money laundering.
In the second part of the operation, trucks carrying waste on the A4 were stopped and officers found a number of them did not have the required EA registration. Investigations into various suspected offences arising from the total operation are continuing.