I have a barrel cap that is charged with the small co2 capsules and it leaks pressure badly I have rubber washers on both sides of the cap and I have tightened it with spanners , I can hear it leaking gas and I only get 1 pints worth of pressure from 1 capsule , any thoughts ? I am considering bottling the rest but I am about 2 thirds of the way through the barrel and on my 2nd box of capsules .I don't know why it's not holding pressure, I will try to get a picture up of the set up .Any suggestions much appreciated, by the way it's a recipe of theakstons old peculiar which I am very pleased with.