I am about to fit a replacement leather piston washer assembly on to an Airsporter MK2 piston.The one I have was bought from Protek supplies and comprises of a nylon head, buffer washer ,leather washer and assembled in that order.I notice on Knibbs's site the same replacement assembly is shown,nylon head,leather washer,buffer washer.

My question is,in which order is the correct way to assemble the new piston head?The original assembly that I removed was nylon head,leather washer,nylon backing washer in that order.