Quote Originally Posted by crowbar View Post
You can get five garden pump (sprayer) washer off the bay for about £12 posted .

I thought the fit of a leather washer was governed by the size of the filler washer in the cup .
If the diameter of this washer is reduced then the leather washer will close up around said washer .
yep, that works as well, I have done this to use spare seals I have that were not actually made to fit a particular gun and are larger than needed but final sizing I do by reducing the "closed" diameter to a sliding fit, As mentioned there are probably various different ways favoured by individuals that will do the same job, every gunsmith has his own tricks of the trade methods.