A bullpup conversion kit for a firearm including a lower receiver with a topside channel that partially receives an upper receiver of the firearm and a magazine well. The firearm includes a trigger pack with a removable trigger. A trigger bar assembly including a trigger bar, a front trigger mount, and a trigger shoe is received within the topside channel. The trigger bar extends along one side of the magazine well. The front trigger mount is disposed on a forward end of the trigger bar. The trigger shoe includes upper and lower ends. The upper end of the trigger shoe is pivotally coupled to the trigger pack in place of the removable trigger. The lower end of the trigger shoe is connected to a rearward end of the trigger bar by a pin. The lower receiver hinges away from the upper receiver about a front hook during disassembly.