Shotgun Zeroing.

[greg11]

I was watching some videos concerning zeroing shotguns. The presenters seem to say that zeroing the shotgun can be accomplished with Slugs, and that this zero will generally indicate the center of the pattern when using shot. Then, once you know the zero of the gun you can pattern the shot load you anticipate using while incorporating your (now known) holdover.

Does this sound about right to you guys? The video doesn't explicitly say there is a connection between your zero with slugs and your zero with shot, but it seems to make sense that they are the same.

 

[BCP]

Zeroing a shotgun would involve changing your mount (modifying your stock), unless you have adjustable bead/sights. If the video was talking about patterning the shotgun, I would have to disagree. In my experience every load has it's own pattern center. I've noticed different slug loads have different points of impact (POI). Changing the choke again changed the POI, even with the same slug load. Changing from slug to shot would most likely have a different POI. Shot is contained in a cup style wad, where as slugs can be touching the bore or be in a sabot. The best way to see your pattern center is to pattern it on paper. Besides, shot loads are a lot cheaper than slug loads!

 

[greg11]

Well, they were talking about using the same loads. They did mention that if you change loads then you'll have to change your holdovers. And they meant "zeroing" loosely I guess. More or less just learning your holdover if you have a nonadjustable sight vs. Zeroing if you had an adjustable.

But generally speaking, will the center of your pattern correlate in any way shape or form to the poi of a slug??

 

[Boomer]

Under some conditions, yes it can work. A birdshot pattern will not exceed 25 yards and stay within a 30" circle zero, and buckshot will extend only a few yards more from an open choke gun. If your open choke, shotgun is equipped with rifle sights zeroed with slugs for a 100 yds, the pattern will center on a target.

On the other hand, with a 30" full choke bead sighted shotgun that drops geese at 65 yards ad nauseam, I wouldn't count on a slug hitting the center of a (large) target much beyond 50 yards.

 

[greg11]

Awesome. I figured there was some sort of correlation (not a solid one per se). I find with shotguns there are so many caveats to every discussion. But taking into account the yardage limitations of buck and bird shot, I would expect that the center of a pattern at 15 yards would correlate with the POI of a 3 round slug group. But then I got thinking about the wad maybe effecting shot differently than the slug ect.. But I guess it only makes sense that they would more or less match up. I guess the key here is to get out and try it. Which I plan on doing today. Thanks guys.

 

[HKMark23]

I've just gone through that exercise with my New Benelli M4 and Bushnell TRS-25 red dot. You'll drop slugs into the center area of an 8 1/2" x 11" sheet of paper at 50 yds no problem. Thats with a 14 1/2" barrel. That done, bird shot at 20 yds comes in centered and roughly 6" low, as you'd expect. Now a 14" M4 is no goose grabber but using slugs to get things near as damn seems to work just fine. Changing brands does change POI significantly so stick with 1 brand for consistency.

Hope this helps.