Chairman Emley Moor F.T.C. 2023 - Misfits champ, HFT extreme champ, NEFTA hunter champ, Midlands Hunter champ, UKAHFT champ.
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As ChrisC says. Manual for Umarex Beretta FS 92 says store empty to relieve pressure on seals etc.
I just spill mine if part full and not shooting. Hope that helps.
Any pistol that seals the CO2 capsule on the end should be emptied after a shooting session to relieve pressure on the seal from the capsule contact, as you say on pistols like the Beretta. Other pistols that seal the gas differently on the seals such as the Aeron, Drulov and others are better left pressurised with gas. Regarding comments on other posts regarding polyurethane, it is a far better material than Nitrile or Viton for sealing longevity.
Baz
Last edited by Benelli B76; 01-09-2016 at 04:15 PM.
BE AN INDEPENDENT THINKER, DON'T FOLLOW THE CROWD
This is the crisis I knew had to come, Distroying the balance Id kept.
Turning around to the next set of lives, Wondering what will come next .
I would be interested to know how you get on with the seals from ChrisC.
I have a Tau 7 which also has an issue with the o-ring in the piercing cap (similar design to Aeron and Drulov). Fitted new o-ring direct from Sureshot, cocked the pistol to take any pressure off the hammer, but yet again on first shot, all CO2 blows out of the seal at the base of the grip. The seal is not visibly damaged, but it distorts in one location (presumably where the CO2 leaks out), then recovers later on.
It seems that the cap might be piercing the CO2 bulb before the cap is fully screwed in (before o-ring is fully compressed). Then maybe the first shot causes a pulse/change in pressure within the C02 chamber in the grip, which causes the pressure on the seal to fluctuate, leading to a distortion/deformation of the o-ring and loss of gas? This is not a case of a cold piercing cap/seal, it even happens on first use, and has happened several times. The design consisting of an o-ring sliding inside the tapered walls of the chamber (as opposed to sealing the end of the chamber) seems to be very susceptible to tolerances on the o-rings and chamber.
This is the crisis I knew had to come, Distroying the balance Id kept.
Turning around to the next set of lives, Wondering what will come next .
I fitted the standard replacement o-ring from a Tau 7 seal kit from Sureshot. I have checked that there are no burrs on the threads of the piercing cap. The inside of the gas chamber is in very good condition. Seems that some o-rings do not provide a satisfactory interference fit. I also bought a second 12gm piercing cap (the spare that came with the pistol was for an 8gm bulb), so will give that a try to see if there is any improvement.
Just for everyone's benefit, there is a vendor on ebay goes by the name of Bohemia seal, and they supply awkward size o-rings even in very low qtys down to singles, have bought from them on a couple of occasions when stuck for a seal.
**WANTED**: WEBLEY PATRIOT MUZZLE END; Any Diana/Original mod.50 parts, especially OPEN SIGHTS
Mark, did the seal fit OK ? I have got a new load in at 90 degree Shore hardness and can keep them for use in the Aeron if yours OK. At the moment I use them in the Crosman 600/677 and Drulov. Also fits valve unit and end cap in Chinese CO2 rifle.
Baz
Last edited by Benelli B76; 19-09-2016 at 11:05 AM.
BE AN INDEPENDENT THINKER, DON'T FOLLOW THE CROWD