New to the forum so hopefully this question hasn't been asked too many times. I'm looking to improve on the trusty smooth bore 12 gauge for next deer season and wondered if it would be more beneficial to go with a .44 mag or .45 colt rifle (or similar) or a rifled slug barrel shotgun. I have my old H&R 20 gauge single shot I have had since I was about 10. Strongly considering have it fitted with a .44 or 410/.45 colt barrel or a rifled slug barrel. I have been told I can fit it with a 12 gauge slug barrel by H&R. What are everyones opinions on this conundrum? If rifle barrel what caliber and if slug barrel fit with a 12 or stick to the 20? All options can be done for about $150 roughly through H&R.