but put it at the back end thereby reducing your Front of Center weight distribution.
That is it in a nutshell right there.
Even slight changes will effect the dynamic spine of your arrow as well, which can also throw it off a little bit. If your shooting light for poundage spined arrows it will show up more readily than if shooting a bit heavier spined one as well.
My friend and I spent a couple hundred dollars, and several months, trying out all of them in several different combinations of fletching, shafts, draw weights, and came to the conclusion that the Nockturnal effected things the least, stayed in better, and lasted longer than any of the others.
That said, I shoot several different bows with different arrows and haven't found the Nockturnals to change much if anything out to 50yds. Even with my lighter Carbon Express arrows shooting from my Drenalin at 70# they still will hit the ear plug with boring regularity if I do my part.
IF you can find some Nockturnal's or order a package, you might even contact them to see if they will send you one to test, I think you would be better off with them, and probably not see quite as much change if any with your set up.
When I say not much of a change, we shoot ear plugs which we stick into our targets, trust me when I say you see a change no matter how small,
two 3 shot groups, two bows same arrows @ 40yds,
I thought I had this showing the lighted nocks, but this was all I got. I don't do groups very often because I end up breaking arrows, that was why we went to shooting the ear plugs. That's also why there aren't any FMJ's in those groups too. It only takes hitting one, to ruin two of them, and that gets expensive fast.