'Workaholics' Star Adam DeVine -- Deadwood Pistol Goes Missing After House Break-In

Adam DeVine lost more than a vehicle during a break-in at his home last weekend ... there's also an antique gun missing ... according to our DeVine family sources.

Law enforcement sources tell TMZ, DeVine's L.A. home was broken into over the weekend and the crooks made off with his brand new truck. We're told there was no surveillance video and right now police have no leads.

DeVine family sources say they are most upset about cops finding an empty gun case ... meaning one or more of DeVine's weapons was also jacked. We're told DeVine has an antique pistol in his collection that his parents bought for him in Deadwood, SD and he's pretty sentimental about it.

The "Workaholics" and "Modern Family" star is clearly pissed ... tweeting, "Luckily it's just stuff and no one was hurt but it just sucks that I work so hard to buy cool stuff and you just steal it because you have no ambition and are too stupid to earn enough money to buy nice things."