Big John - all three blades open - or did you try opening just one ?

Don't get me wrong, I'm not challenging you, but it seems like having just one open would upset the flight.

I too have NAP SpitFire 100's, and I haven't had a problem. As dumb as it sounds, I'd think the likely cause would be practicing with 85 grain field points and then switching to 100 grain expandables or something like that.

How are they hitting ? I mean, are they consistently low, high or off to one side or the other, or are they more or less erratic ?

Did you change anything besides the tips (ie: draw weight, length, rest, etc.) ?