Been shooting my new bow, Fred Bear TRX (36" ATA length) with Tru Fire rope style caliper release...

Sighted it in with 2 pins, 20 & 30 yards and when I do my part it is plenty accurate...

The thing is, most of the time, the arrow flies true and hits where I aim, but one and a while, (it is never the same arrow, so I know it is me) I get one that seems to wobble (a little but) but still hits where I aim...

So I know I am close, and the bow shoots real well, I just dont know what I should do... I mean, I am shooting 3 shot groups at right around 3" at 30 yards so it is plenty accurate for deer

opinions? Also, what is the most accurate expandable broadhead?