doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Barrel regulation - how close is close enough?

Hi All,

For a SxS shotgun, how close should the points of impact of the barrels be to one another?

TIA

--shinbone

I think everyone would like their guns to print each barrel exactly on top of the other. However, more likely they settle for pretty close. I think its pretty subjective, but boils down to the ability to make a kill or break a clay. I'm thinking something like 15-20% of the pattern diameter would be a limit.

I would want the center of both patterns to be within an inch or two of each other at 10 yards. The barrel centers are only about 1-1/4" apart. How far apart should the pattern centers be, all the way out? This idea some have that the patterns are some considerable distance apart in the beginning and then somehow come together at 25 or 40 yards, like a bowlegged woman, is total nonsense!

Just remember that POI can be changed by different cartridge loadings and also by the way a gun is held by the shooter. As I understand it, the barrels are regulated in such a way that they actually cross a very short distance in front of the muzzle. The flex of the gun when shot supposedly moves the crossing point out to a distance approximating 40 yards or so. This refers to horizontal POI. I'm not sure how vertical is affected, if any, by these factors.

Interesting points, everyone.

If the distance between points of impact is based on a percentage of pattern diameter, what choke size would be the basis for that pattern?

Put another way, say at 20 yds., what is the maximum allowed distance between the barrels POIs? 1", 2", 4", 8", 12" . . . ?

--shinbone

Shinbone-There isn't a set of standards written down somewhere. It all boils down to what the customer, and therefore the maker, demand. Personally, I think 6-8 inches at 40 yds is as much as I'd take. Less is better.

Hammergun - Thanks for your input.

I am pretty sure, too, that there is not some mandated universal standard written down somewhere. Also, I would expect a customer can request a minimum POIs deviation that the maker then meets in only the highest-end custom shotguns.

I would expect the issue of barrel regulation is treated differently in double rifles than double shotguns. I am just wondering about double shotguns.

In the case of non-custom double shotguns, I am thinking each manufacturer has a barrel regulation standard they generally aim for. Such information I am sure is confidential, however.

I am just trying to determine the general consensus of the cut-off between what POIs deviation is acceptable versus too much in a high quality mass produced double shotgun? In other words, how much deviation should a shotgun shooter tolerate?

--shinbone

It doesn't matter what choke size we're talking about. For example, a little pattern out of a .410 would want the patterns to match within a few inches, where a 10g pattern may be more tolerant. These assessments would be at distances the gun would be used for game/clays.

I understand, one of the 'B' gun mfgs. says a difference of 4" at 40 yds. is acceptable.

4" at 40 yards would be acceptble to me, as well. From there back to the muzzles, the separation would be less. 4" at 10 yards would NOT be acceptable, to me.