Best bet is to get a diamond sharpener made by dmt. £30ish, will get you the diafold, which is a double sided jobbie, will sharpen 10 times quicker than an oil stone, and cleaner to. couple of strokes on these , is enough to get razor results. and folds small enough to carry in your shooting jacket. blue is course , red is medium, and green is fine, have found the blue / red combo is best.