would the use of slower burning powder say 48.6g vit n165 with 95 grain bergers which produce exellent groups at 200y in my 243 give slightly extended barrel life than the use of faster burning propellents such as vit n150 or n160 etc, i know that there is a slight increase in charge with the slower powders and on inspection after firing seems to be a little more carbon fouling left in bore in comparission to the faster powders, your views would be apprecited regards paul T.