This is Chance's Flintlock from the hit game Forsaken. 

Chance is a gambler and 99% of gamblers quit before they win big.

This Flintlock is based off the Pirate's Flintlock gear in Roblox however in Forsaken, the Flintlock is slightly thinner hence that is why the barrel is an oval.

Feel free to upsize the model to make it fit or you just want this as a decoration or cosplay weapon.