Assembled my pcp.when trying to cock the gun to start filling it up again(from zero air) it wont cock..is this normal..or not.cocking would d help me refill from a hand pump.the trigger assembly was never removed during disassembly but i did push the hammer to lock with the breech while assembling the pcp ..where it did travel over the trigger sear.what can be the problem.can i fill it without cocking using the hand pump.