doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Inherent inaccuracy of a SXS-How Much?

How much inherent inaccuracy is there in a SXS versus a single barrel?

With a gun regulated to hit square at 40 yards, I suppose it would only matter at 20 or 60 yards.

I would guess it is only an inch or two.

Thanks
Lou

What we talking about regular bird shot sxs or slug shooter?
You guess inaccuracy an inch or two - well, only best guns could show such accuracy at 40 yards or good slug shooters. Usually 4 inches is ok for regular sxs.

BY "inherent" I assume you are refering to the argument offered for the so called single sighting plane as opposed to the (erroneous) double sighting plane of the side by side. Both actually have a single sighting plane, but it is argued that a SxS may require more precise fitting, to the shooter, for the rear sight (eye) to match properly with the front bead. I suggest this would be a factor more applicable to guns with concave ribs or swamped ribs rather than with raised solid or vented ribs. The former found more on light game guns. Some argue that the barrel convergance of SxS guns creats an angle that makes determining lead on crossing shots more complicated? I think that is more due to the SXS having more to look at when your supposed to be looking at the target. You often hear people say that their problem with the SxS is that the two barrels confuse them. Their just not use to looking straight down the middle where the SxS's single sighting plane is located. Also with SxSs or O/Us the point of impact of two barrels is a more complicated build than for a single barreled gun. Finally, a single barrel gun that does not fit properly can shoot off as well. A shooter, on a trap range, can shoulder his gun and purposefully align his front and mid beads, position his eye to the center of the rib and call for the bird. Many do this. It just isn't what the very good shooters do. This is just all theory, in my case, if I be honest.

On a correctly regulated set of barrels we are talking about much less error than I can hold the gun to or even see when I shoot it. If the barrels had the same POI at 40 yards the math indicates there would be 0.43" (3/8") difference at 20 yards and the same at 60 yards.

This is for a 12 gauge. 0.730" plus 0.060" plus 0.060" equals 0.850 which give centerline to centerline of the barrels at the muzzle. Divide .850 by 2 to get the POIs half to 40 yards and half again past 40 yards.

Best,

Mike

Bushmaster:
I don't mean to sound flippant here, but I assume you are talking about shotguns. If that is indeed the case, then the very nature of the beast makes "an inch or two" astronomically academic. Which, I may assure you, it is.

Best, Kensal

I've never seen an inherently inaccurate SxS although i have seen a few inherently inaccurate SxS shooters.

Glad to know it is so small I will never notice with target shot.

If the difference was a foot that would make a difference

It's a shotgun - get over it. Worry about something that matters.

Dr.WtS

Very good answers and important details, ben-t and Amarillo Mike!
Thank you,

If everybody did that, Dave could close this thing down.

There have been 100 response threads with questions more trivial than this one.

The answer is... as discussed in the painful series of discussions about a mystery Grulla...

'Inherent inaccuracy' is a poor term, and probably would more apply to double rifles, or for that matter a P-51. The two barrels can only intersect at one point, or be parallel to each other. There is no other solution, other than divergence which we've determined to be undesirable.

SxS shotguns and double rifles must compensate for the fact that the bores do not pass through the vertical axis of the firearm.

They do so by converging the barrels ever so slightly at the muzzle, so that during 'barrel time' the recoil displaces the fired barrel to parallel with the original sight line.

There are several factors that can affect the final outcome.

A properly regulated double shotgun, firing the load it was regulated for, by a person whom it fits, has zero 'inherent inaccuracy'. It shoots both barrels where pointed.