All Springer/NP/PCP Air Gun Discussion General > Crosman-Benjamin Air Gun Gate

Trail nitro piston exchange


Hello everyone
I would like to swap out the nitro piston that is in the trail np xl .177 that I have. I was wondering if I got a smaller gas ram if it would calm it down some? I shoot exact monster diablos 13.4 gr to help calm it down.

Robert 5mm:
The compression chamber the piston rides in is a diameter along with the piston and piston seal.
The gas ram just pushes on the piston and is not part of the diameter of the piston/chamber.

A spring piston can be de-tuned but the Nitro Piston gas-ram is another story - I do not think you can let gas out of the gas-ram on a Crosman.

The answer to your question about a smaller gas spring (Nitro Piston) calming it down some is probably yes.  I believe the gas springs from the NP2 series are the same diameter but I do not know about the length.  The gas springs from the Nitro Piston series are a bit smaller in diameter but again, I do not know about length.  You may need to do a bit of experimentation, learning as you go.

Robert 5mm:
If the gas-rams of the different Crosman/Benjamin models are the same dimensions - you should be able to switch them.

My NP2 piston is not the same model number as the NP XL piston nor the NP piston. ( My NP2 gas-ram does not have a valve ).

If the different model gas-rams are different lengths then the stroke of the piston is probably different. ( my earlier post was about the bore ).

Piston latch-up to trigger and stroke of the piston to end on compression chamber ???

Sounds like a project.

 Late to the party, but thought this might be useful. The NP in the Trail NP XL is unique. The overall length is 300 mm, the cylinder is 169 mm and the shaft is 131 mm. The diameter is 18 mm (same as the rest of them), but the length is a good 19 to 20+ mm longer. The shaft is also 20-30 mm longer than the others. To make a lower powered NP work you would have to shim it considerably, if that would even work.
  A new seal would tame the recoil and smooth things out considerably. I use this one, Pyramyd part # PY-A-4098 Of course, if the power is the problem the new seal will make it worse-it will pick up some power. If taming the recoil is the goal, that seal will help.
  As a side note, deburr the stamped slots in the air chamber before installing the new seal. The manufacturing process leaves sharp edges that cut the seal lip.


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