I have a rifle with a 20 inch barrel, for coyotes and long range pig killing. I have a rifle with a 16 inch barrel for close up hog killing, and I have an SBR with a 14 inch barrel, for when the zombies come. I have one more lower and upper, and I am thinking of building an 18 inch gun. does anyone have a rifle with an 18 inch barrel? Is the accuracey better than a 16, worse than a 20, the way to go, or a waist of time?