FAS 604 pistol :: how long to leave cocked?

[MattW]

Hi All,

I have a new (to me) FAS 604 single stroke pneumatic target pistol.

As it suffered the (apparently not uncommon) o-ring deterioration which these pistols are prone to, I recently stripped it, cleaned everything and replaced all internal o-rings and seals using the recommended lubricants where necessary.

It now runs great, and is a delight to shoot (and I'm completely addicted to punching holes in paper and the quest for better scores!).

However, one thing which isn't covered in it's documentation and which I've not been able to find an answer to relates to how long you should (or can) leave it cocked and pressurised for? - My usual cycle from cocking and loading to firing probably takes an average of 10 -15 seconds or so, but on occasion (e.g. when tired and losing concentration), I do put it down compose myself and readdress the target (sometimes more than once). This obviously increases the time it is cocked and 'under pressure'. I am however concerned that this will this harm the pistol, or that there is a danger that it will lose some charge and affect my zero?

If anyone has any experience of these pistols and could offer any advice, it would be greatly appreciated!

cheers

Matt

[pennineway.fswo]

Hi Matt
Leaving the pistol charged will not do it any harm, and it should not lose pressure when left charged for any lenght of time. Obviously if the pistol was to be left charged for days or weeks on end, then some air may pass the seal on the piston or past the exhaust valve and the gun lose a little pressure. One of the tests on buying a pneumatic like the FAS is to cock it(without a pellet), leave it cocked for 10 minutes and then discharge the gun. If there is a healthy bang, then the seals are probably OK. Obviously it is not recommended to leave it loaded with a pellet in it for safety reasons
I have a Walther LP3 which is a single stroke pneumatic and if I cock the action, it will hold the charge for weeks on end and still make a crack on pulling the trigger.
Checking with a chronograph is the best way of telling if there is any loss of pressure with time. If you do not have access to a chronograph and you think the gun is losing air then the Fas 604 spits out 7 grain wadcutter pellets at about 400 ft/sec which is just enough to punch neat holes at 10 metres in the standard UIT/NSRA 10 metre target.
If you leave the gun charged for 2 or 3 minutes and then on firing, the holes are torn, this is also a good indicater that the seals are leaking
John

[MattW]

Thanks for the reply John! - That's set my mind at rest

I have a Chrony F1 - now that I know I'm not going to damage anything, I'll try a test to see how it holds pressure tonight!

cheers
MAtt