Being an Ohio deer hunter for over 50 years and restricted pretty much to
the s.g. & slugs some of
us'ns who strived to make the smoothbore & rifled slugs shoot with better accuracy came up with some solutions to the lack of accuracy.
I'm going back a lot of decades for this.
Keys:
Sights. Not just a bead front.
No double barrel s.g. They won't regulate a slug from each barrel nearly well
enough.
Scope is a good idea, but at least rifle sights.
Cyl or I/C seems to work best but some do well with a mod choke.
Rifled choke tubes didn't do much for us & we tried a bunch of 'em.
Keep the barrel to receiver tight even if shiming must be used.
Keep the barrel clean of lead deposites from the soft rifled slugs.
(we even learned how to lube the slug inside the hull)
With the above tricks we could get at least 3" at 75 yards with almost any s.g. predominantly the 870 and Mossy 500. Some Browning A-5/s were remarkable.
Every barrel by different makers seems to prefer certain ammo.
We did best with Win. & Brenneke K.O. in 2 3/4" loads. Sometimes we could get 3" and better at 100 yards making the smoothbore with rifled slugs a viable 100 yard deer getter.
Of course, back then, our group of deer hunters went through cases of slugs in the pursuit of accuracy. There were 5 of us that had our shotguns drilled & taped for scope mounts. Now they come that way.
We've gone through the rifled barrel & expensive sabot ammo also often with little accuracy gain. All ammo & barrel specific of course.
Ohio is going to proper rifles this fall in certain calibers so I'm done getting beat to death with 12 bore slugs.
Now I can get beat to death with my 45-70.