An injection device is disclosed including a housing assembly defining a pair of ramps and adapted to hold a medicament cartridge. A driver is adapted to advance the piston within the cartridge. A plunger having a pair of arms is moveable between a retracted position and an advanced position. Each of the arms are engageable with a respective one of the ramps as the plunger is advanced. A braking mechanism may include braking members on the arms and braking tracks proximate the ramps. Excessive force exerted on the plunger may flex the arms and engage the braking members with the braking tracks. The plunger arms may be connected together by a material bridge that biases the plunger arms apart from each other. The arms may include detents that engage to prevent the arms from moving due to the biasing force of the material bridge when the arms are in the fully retracted position.
