Originally Posted by AirArmsDavid
Thanks for info Chris.
Why would it sometimes be needed and sometimes not?
I guess it gives just that little bit more sealing pressure as the stabiliser comes forward and seals, so logically a higher pressure rifle would perhaps need one, not lower?
Just trying to figure out what it does!?
The reason for the washer is to raise the height of the transfer port to make a seal against the muzzle tube,it depends on how it leaves the factory.It is that thin it can only be used once,as it compresses and becomes damaged.
The best thing to use is PTFE tape,only wrap it around the transfer port once.After you have done this,load the gun with a pellet in.Now apply talcom powder along both sides of the transfer port and also around the top edge,now fire thr gun.Any evidence of a leak will be instantly seen,it's better if you do this with the scope off.After you have done this remove the remaining powder using a vacum cleaner.If it hasn't sealed,then remove the PTFE tape and wrap it around twice,keep doing it untill it seals.Once you have obtained a seal check that the muzzle tube passes over the port without any resistance,then LIGHTLY lube the green o ring.
Hope this is of help to you.
Forgot to say,don't apply the PTFE tape to the thread ,twist the tape first untill it looks like string,then wrap it around the top where the thread starts.