Styer LP50

Bought a used LP50 this week. What a cool pistol!  Set up a 10m range in my basement. No ammo worry with that gun. Love it!  Question: is it recommended to unscrew the cylinder to relieve pressure on the seals between sessions?
Kurt

I keep the air cylinder screwed into my pistol, just as with my PCP Riffles, I do not remove the bottles, or deplete the air from them. It's not good to let them sit without air in them. Even my spare cylinder has air in it.

A static seal will either seal or not.  More damage will accrue with unnecessary removals.

A good article on air pistol and rifle maintenance by Scott Pilkington: https://www.ssusa.org/articles/2016/10/19/air-gun-maintenance

Preserve the Life of your Air Gun
One thing you can do to preserve the life of your air gun is unscrew the cylinder every time you finish shooting it for the day. Unscrew it enough that you hear the air “whoosh” out of the regulator. Leave the cylinder attached to the gun to prevent dirt or other foreign objects getting on the threads. When you get ready to re-install the cylinder, unscrew it all the way out first, and then start back in to avoid pinching the sealing o-ring. The reason for releasing the air is to take the pressure off the regulator springs and o-rings—the heart of a modern CA match rifle. The regulator is what steps the 3,000 PSI air in the cylinder down to around 850 PSI to give a consistent shot each time you pull the trigger.

I unscrew and remove the air cylinders after use. Since the pistol is stored in a case dirt is not a concern.

The seals that might wear from removing are cheap and plentiful. The firing valve is a $45 part, and if it is under constant pressure, that seal can get flattened. Having the spring washers, (Belleville) always under pressure might also change the value of your regulator over time. Putting a dab of SuperLube on your cylinder adapter and o-ring will dramatically reduce wear on both. I have an LP10. I have changed out 3 fill adapter orings in the last seven years. You can buy a bag of 100 of them from McMaster Carr for $4.

I do just as Pilkington recommends.  I also drain my air compressor in the garage every time I'm done with it to keep the pressure off of the valves.  To me it makes sense.

John