i don't know if anyone can help me with this issue but here goes.
I bought a CA90 proline from someone in my area and the gun doesn't fire, he had warned me that when he bought it also used that it wasn't working but i figured i could fix it. now here is what it does.
When i fire it without a magazine on i can clearly see the air nozzle that is at the end of the mech box going back and forth literally going under the hop up port which i don't think is normal.
Any advice ?