That current limiting circuit will always have quite a big voltage drop, at least 0.6 V, and there could be loads of heat generated in the transistor.
For currents that big, you need some serious power transistors. You should also have a circuit with a much lower value sensing resistor, and an amplifier to control the current. You should also have a connection to ground, so that you can have a supply to run the amplifier and to turn on the transistor. That will mean that the voltage drop will be very small when you don't need to limit the current.