12 guage, Mike. #10 shot.....
Not effective, but fun!
I use that that white stuff powder in round can (I know this helps) from Soldotna Hardware around the perimiter of house and garage. Sometimes 2X year, this year only once. Works good. Really irritating listening all night long to the little bastards chewing on the framing...
Home Depot or maybe Walmart may have it too.
Your nests are pobably in some of the big spruce trunks on their way to dying and falling on your house, your horses, your dog, your car.
Clearcut and burn!