The spread out of a rifled barrel is significantly greater than you'll get out of a smoothbore, but as long as you use a larger shot size and keep your distance very short (no more than about 10'), they're still effective on small pests out of a conventional handgun.
For those who want much tighter patterns using either conventional .410 shotshells or with handgun caliber shotshells, Thompson/Center has long had a dual purpose .45 Colt/.410 barrel that has a screw-in choke with internal ribs that run parallel to the barrel that serve to stop the spinning of shot charges when shooting anything but conventional bullet .45 Colt loads.
You just have to check and double check and double-double check that the choke tube is removed before shooting conventional .45 Colt loads!
