Reply To: Anyone shot a 22 Nova Freedom or Seneca Aspen? Feedback wanted please…

Forums PCP Airguns Anyone shot a 22 Nova Freedom or Seneca Aspen? Feedback wanted please… Reply To: Anyone shot a 22 Nova Freedom or Seneca Aspen? Feedback wanted please…

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monsterpcp
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S97

Have you determined why the pump is binding? 

 

The part that binds is the small, pencil size piston in the final chamber tube. This is where the highest psi air is pushed into the reservoir. Compressing air creates its own heat, made worse by o-ring friction. From the factory, the piston is sealed by a single, wide o-ring. You can't oil that chamber tube and piston directly: Oil must work its way there from the oiling hole and through the other chambers. So, rather than slide smoothly, the o-ring(s) wants to jam between the tube and piston. Per instructions and help from poster Butch (search my posts), I replaced the (wide) worn o-ring with two (2) 006 Buna Rubber rings, side by side in the slot. Next time, I'm going to try 006 polyurethane rings, 70 Duro.

Why does it bind on some occasions? Hard to say. My most recent binding episode was on a 85 degree day with sun shining on the black gun while I was shooting. It's random, and later in that session it worked fine. Perhaps oil is working its way through even as I was shooting.