granulars of powder
I shot my Mountaineer last weekend, ran about 10 shots through it before it got dark. It seemed to take 3 shots to settle some what. 1st shot on a clean barrel and then the next 5 was on a fouled barrel no swabbing. 2nd and 3rd was high about 1 inch, 4th was dead center 5th was a flyer high and right about 5 inches and the 6th was stacked with the 4th. Not sure what happened on the 5th one I didn't feel like I pulled or done anything out of the ordinary. I then cleaned the gun completely to do another 3 shot group just like I would hunting. Popped 2 caps loaded and shot the three shot group. 1st was 1in low and slightly right next two was 1.5 inches high and split the center (probably me).
My question is when I took it down to clean again I noticed 2 granules of powder, what causes the incomplete burn? Not enough seating pressure? My load was 90 grains volume BH209 with 250 grain Hornady xtp. and CCI 209 Primers. What do you think would cause one to not group?