#8 is too light for squirrel, leesun you like picking a [bleep] load of shot out of your squirrels. It will kill them. But it leaves a lot of holes and lot of shot in the meat.

I don't hunt with a .410. Smallest I hunt with is a 20 guage. Last season I tried #5s and they did very well and mostly shot through. In 12 gauge, I like #4, 5 or 6.

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https://vcdl.org/