"donut" shape in your patterns?

[SCMtns]

Just curious-- of those of you who have patterned your shotguns with different loads, how many times have you encountered a "donut" pattern? I'm referring to a pattern that scatters a ring of pellets around your point of aim, leaving the actual point of aim untouched. Have you ever had a barrel that was prone to doing this with various loads?

I've never seen this myself, but I've only tested a couple of shotguns for patterns over the years. I know there's a lot more experience around here than I have...

Thanks.

 

[JWF III]

Everytime that I've shot a shotshell (not slug) from a rifled choke.

I was wanting a cheaper "Diffusion" choke for my 870. It didn't work out so well. Briley's Diffusion choke patterns perfect, I don't know what they do differently. All I've been able to guess is that they us less twist.

Wyman

 

[hometheaterman]

My 870 I had wanted to do this. I can't remember what shells it did it with though. I want to think it was 3 1/2" 00 buck shot but it might have been 3" 00 buck. I tried a full and modified choke and can't remember which one did it. I found out the 3" 000 buck and the full choke really works well. I wish they made a 3 1/2" 000 buck.

 

[inSight-NEO]

From what I understand, this phenomenon is normal. Keep in mind, various things can attribute to this "donut" pattern when using buckshot. Things such as ammo brand/type, barrel/bore quality, choke type, distance from target, etc., all have an affect to one degree or another. For instance, my Benelli SNT (with chrome lined smoothbore) patterns better/tighter than my Mossberg 590 smoothbore, regardless of ammo and distance. But, they both pattern far better and tighter, when using certain ammo (Federal LE Tactical 00 Buck, for instance) vs others.

After all, "patterning" a shotgun is necessary due to this exact "spreading" pattern as it occurs at various rates/distances, depending on the weapon used and ammo fired. Within my limited experience, it seems as though distance (primarily) and ammo selection (to a degree) have had the greatest impact on pattern shape/size.

 

[Fred Fuller]

The only time I have seen it happen in a smoothbore barrel was when shooting roll-crimped buckshot loads with a heavy card stock over-shot wad.

lpl

 

[cgs500]

The box O truth

Check this SITE out.
It is a pretty fun site to look over.

 

[SCMtns]

Thanks, guys! All very informative. I've been over to the box o' truth a number of times, but never noticed that he tested shotguns before. So thanks for that. It stands to reason that a rifled bore would sling pellets to the outside of the pattern, but I don't own a rifled barrel for any of my shotguns. I guess I was wondering more if anybody had ever had a shotgun that was prone to throwing donut patterns regarless of load choice or choke, but it doesn't sound like it. Like I said, I've never seen it myself, and it sounds like y'all have only seen it on rare occasions with particular loads in particular barrels. Good to know.

Thanks again.

 

[MortalWombat]

mmmm.... donuts

 

[Loyalist Dave]

It's not really something that often occurs with factory loads, but I have seen it when folks use too much BP in a ML shotgun or in a BP shell, as well as when folks "juice" up their reloads toward magnum velocity but don't correct for that with shot cups. Seems to be a function of whether or not the shot column "twists" on its own as it heads toward the muzzle, and faster MV = amplification of the effect.

Back in the ML days it appears to have been known..., seems that they are discovering more and more "rifled" guns were assumed to be that way as they could see the grooves at the muzzle, but..., when they check the bore they find no twist so the barrels are gooved not rifled. This gives a non-choked shot column a bit better performance, and works just fine for a round ball at under 100 yards too. So more guns were "double duty" than first thought.

Funny thing, you can find turkey chokes now with "straight rifling" so to help maximize that shot column thus preventing any twist as it exits the muzzle. What was old is now new.

LD

 

[inSight-NEO]

The only time I have seen it happen in a smoothbore barrel was when shooting roll-crimped buckshot loads with a heavy card stock over-shot wad.

I guess I was confusing a relatively spread-out pattern (firing 00 buck through a smoothbore Mossberg 590) for a "donut" pattern. Of course, I was firing at 20 to 25 yards, so I'm sure this had something to do with it.

 

[Pete409]

I've NEVER seen a donut pattern from a shotgun, but then again, I've only shot about 1,000 different patterns from perhaps 100 different barrel/choke combinations, so maybe I just haven't shot enough to find one.