It seems to me i have purchased somewhere near 28 vent liner from Lehigh. The flash hole i measured in them were 0.032". The flash hole in the two Knight nfpj breech plug i purchased, measured. 0.031". If this difference isn't due to them being coated, my question is why the difference? Why? Why is the flash hole of the Lehigh vent liner 0.001" smaller in the Knight nfpj breech plug, than it is when Lehigh sells, and sends it to my house?