Remove bolt and stick your finger in where the barrel screws in. If the air is coming from the hole there then your valve is the cause. If no air is coming from that hole then your ram is the cause.
Full flow scenario:
From valve: Make sure that you CANNOT see the valve spring by removing the LPR/valve cap. Remove the valve (always do this through the rear of the body, going through the front will cut the valve o-rings causing this problem) and replace the o-rings. If the o-rings already look fine then check the valve for any damage.
From ram: Remove the ram housing from the body and replace the large o-ring closest to the hammer. If it still leaks the take the ram out of the ram housing, by removing the hammer from the ram and sliding the ram out of the back, and replace the small o-ring inside the ram housing near the tip (same spot as the large one just on the inside).
Small leak scenario:
From valve: Remove the valve, press the valve pin and look for any debris on the inside edge of the pin and for any scratches on the valve where the pin and valve meet. If there is no debris replace the valve o-ring on the side that is closest to the LPR.
From ram: Remove the ram assembly and apply a little bit of Dow 33 to the outer o-rings and on the ram shaft (cycle the ram a few times to get the lube in there) and replace.
If it still leaks replace the large o-ring closest to the hammer.
If it still leaks the take the ram out of the ram housing, by removing the hammer from the ram and sliding the ram out of the back, and replace the small o-ring inside the ram housing near the tip (same spot as the large one just on the inside).