Recently I found out that for all of you using spring air guns that the heavier the pellet the tighter your group! I went from using 7.4 grain pellets in my 177 and getting roughly an inch and a quarter at 30-40 yards. I now use some 10.5 grain cross man premiers. My groups now are roughly three quarters if an inch. About half an inch of difference is all that it takes. Also bucks the wind a little bit more and packs a bit more of a whollup.