Well, based on the title, one can guess I have been playing around with slugs and read posts trying to garner knowledge/ understanding about this subject. All I can say is this stuff is involved! Some would say "well, just keep shooting until you find one that does well" . Alright, fair enough, but the variables are staggering. I've read parameters of importance regarding length, diameter, center of mass, and base- boat tail, flat base, dish base, cup base, cone, ouch! Then obviously there is grain weight where 1-5 g difference has big impact on results. Then you have composition of slug some advocate pure lead to minimize barrel wear caused by slugs with more antimony or whatever compounds added for what is deemed proper mix for their projectile. Lastly, I don't wish to shoot every type slug in every brand in a particular caliber- a huge amount of time and cost invested . To try to narrow the search down you can measure barrel diameter, now , I've again read some say "It's the bore diameter" while others swear "It's the groove diameter" and let's not forget velocity and twist rate which have advocates over a wide spectrum. There has to be a general way to narrow this process down, and I'm convinced it's the barrel diameter but, slugs come with general measurements like pellets and I've seen the variation differences in a tin of pellets as well as their effect on accuracy. Now a slug has far more contact area in a barrel than a pellet so the hundreth of a mm difference in diameter is that much more impactful on the accuracy. I like they way slugs shoot, but it appears to be a daunting task to find "the one".
on, but with the quantity of lightweight slugs that I've sent downrange, you won't change my mind. 
