I have been reloading 45-70's for about a month now with good result, but I wish to avoid a potential disaster. Have a volumes of reloading manuals, some of these manual speak of having to use a 1/2 gr polyester fiber wad, 5/8" square X 1/4" thick over powder. Gone to the store and no one seems to know what I am talking about. Been avoiding the issue the wrong way by using the manuals that do not designate the polyester fiber wad. My question is, what exactly is this wad fiber and is it necessary to insure powder ignition?