Officers continued their fight against organised crime with an operation at an industrial unit in Coventry.
They found a Scorpion machine gun and two shotguns stuffed in bags that were hidden in walls.
Police also said that on the same day, in an unrelated series of raids across Coventry and Warwickshire, they "recovered 11.5kg of cocaine, amphetamines and cannabis as well as a drugs press and mixing agents and a blank firing gun converted into a live firearm."
A statement continued: "We also seized around £420,000 in cash.
"The drugs have an estimated street value of £500,000, making it one of our biggest seizures in recent times."
Five people were arrested in the raids which took place on Friday.
"Three people were arrested and charged, and two more were arrested and then released pending investigation," West Midlands Police confirmed.
The investigation into the guns found in the wall is ongoing.
Chief Inspector Dave Amos said: "These are some fantastic recoveries of drugs and weapons that would undoubtedly have been used to spread fear, misery and violence on the streets of the West Midlands.
"We won’t stop in our pursuit of those who deal drugs and trade in firearms. They represent a serious threat and we be relentless in our efforts to take them off the streets.
"It’s only thanks to information we gather from the community that we are able to tackle this threat.
"If you have information that could help us make the streets safer, I’d urge you to do the right thing and get in touch."
Anyone with information is being encouraged to get in touch with the police "via Live Chat at west-midlands.police.uk, or Crimestoppers anonymously on 0800 555 111".