IS THIS NORMAL pellet behaviour?

I really need a camera! - I was playing around @120yrds 34gr.@870fps. I had a dark background,and sunlight on the pellet for last 50yrds of flight-This is what I'm seeing-As the pellet leaves the air protected by the100x100 building on the property 30yrds away,IT rolls into the 10 oclock 15mph wind for a sec. then spends the rest of its flight trying to right itself diving back to the target.for two groups sometimes
 
Got a high speed camera in the classifies. The wind coming over the building might be playing havoc with your pellet. Since I can't see what you are dealing with think of it this way....What do you think it would look like if it was water flowing over and around the building. Air and water act a lot a alike that is what your pellet is experiencing. Think water that could be a lot of eddies. Hope this helps.