Years ago I loaded some .223s with green dot shotgun powder. I got the powder charge set wrong and they were probably 30% below the book. Rather than pull the bullets (I didn't have a bullet puller) I shot them in a mini 14 I kept on my tractor for varmints. The loads wouldn't work the action but they disposed of a lot of skunks, rats, groundhogs and snakes when I was mowing hay or bush hogging. Most shots were about 10 to 50 feet so accuracy was not critical. They didn't seem much louder than the noise of the tractor and machinery.