You're supposed to wash it in order to get the stuff called 'sizeing"(?) out of the material.It's something left from the manufacturing process.
Paul...That "sizing" is a kind of starch...I'm told.
Mr. Webster seez;
size: any of various glutinous materials (as a preperation of glue, flour, varnish, or resin) used for filling the pores in surfaces of paper, textiles, leather, or plastics. as well as applying color or metal leaf (as in book edges or covers).
I'm also told it's purpose is for the "looks" or presentation of the fabric, nothing more.... IOW, To make the fabric handle and look better to the consumer.
Another, often overlooked reason for washing, is because if you don't, it does NOT take to the lube evenly, as the pores of the fabric are filled with this sizing material.
Also, it will "swell" when allowed to sit after being lubed,.... the lube starts to break down the sizing and penetrates the fabric causing it to swell...This of course can be benefical....to a certain point.
At the same time it can affect the POI if every round is not fired at roughly the same length of time after being loaded....IMHO, this part is splitting some mighty fine hairs, but none the less, it does seem possible...maybe?
I can not say for sure if any of this is fact. I have been told this for several years now, and since it makes at least some sense, I have followed the rule of washing the material before cutting and lubeing.
I have seen as much as .004 / .006 difference, (and on at least one occasion)as much as .010, in material that was measured before and after washing.
Keep in mind, a lot of this "information" comes from the old farts that hang out at the range. I'm sure ya know the kind...the ones who use the estrous of the female flea in that magic concoction of lube that wins every match...the same fellows who know who shot President Kennedy... I'm sure you've seen 'em around, they seem to be everywhere....
Respectfully, Russ