Well, I tried washing, lubing an pellet sizing, and il stick to just the pellet sizing, it got down to 1fps variation over 15-20 shots with the h&n, without sizing it was about 6-8 fps difference, and then BAM, back to 1-2fps variation,I couldn't believe it tbh. It was with a combro though, so how reliable it is I don't know, but its bloody accurate, an really good on air lol