Colorado- you can effectively polish the bores by scrubbing with 4-ought steel wool on a jag. It won't hurt the bores.
: As well, you could use FLITZ polish on a cloth patch on a jag and run it up and down the bores. This will also polish, but may not remove the 'feather'(if there) on the edges of the lands, which can cut patches and induce inacurracy. The steel wool will remove this sharp 'feather'. Feather is caused when cut rifing, and won't be there if the bores are button rifled. Cutting or burning through the patches will cause inaccuracy. The muzzles must be polished and crowned such that seating a tight combination doens't cut the patches.
: A hunting rifle should be able to fire at least 5 shots from each bore without needing wiping.
: A major cause of inaccuracy is poor or innapropriate lube. Some rifles demand different lubes be used. It is an idiosyncracy of rifles - they normally require different loads to shoot their best, rifle to rifle. I suppose this may also mean, barrel to barrel, so some comprimises might have to be made. Working up loads is not an instant success job, normally, sometimes taming many trips tyring various different methods and patches, ball sizes, etc, before 'arriving' at the best load. Having 2 barrels joined together makes this 'job' take at least twice the time of a single barrel. Success depends on what your 'parameters' of an acceptable load are.
: I know of guys who accept 5" at 25yds. as being OK, while others will only accept 3/4" at 50yds as being permissable. Some give up and clean after each shot as their load of lube,patch or ball won't allow repeated shooting without wiping. Guys who load like this are never in the winners circle at our local B.C. matches.
: I see other guys with the .72 Kodiacs shooting upwards of 130gr.@f- I suggest trying the more 'healthy' loads and see if the barrels shoot parallel with a larger powder charge. I've always thought heavier loads would spread the balls. It could be the small charges of 3 drams just isn't enough powder. From a hunting standpoint for elk or bear, it certainly isn't.
: Personally, I'd be trying 4 to 5 drams and see how it shoots. Note that the patch & lubericant must be up to the job.