I thought this was a simple explanation of what regulating means, and what factors can play into it...

Regulation of Double Rifles - If the two barrels of a double-barrel shotgun shot 3" apart at 25 yards, not many people would notice because the pattern from each barrel, spreading two feet across at that range, would largely overlap. If, on the other hand, the two barrels of a double rifle shot 3" apart at 25 yards, it would probably shoot 6" apart at 50 yards and 12" apart at 100 yards, limiting its utility.

One cannot build a double rifle, using sophisticated mass-production machinery with barrels perfectly parallel and expect both barrels to shoot to a common point of impact. While the bullet is traveling down the right barrel (of a side-by-side double rifle) the rifle will be pushed up and to the right, throwing the bullet up and to the right when it exits the muzzle. While the bullet is traveling down the left barrel, the rifle will be pushed up and to the left, throwing the bullet up and to the left when it exits the muzzle. To compensate for the movement of a double rifle while bullets are traveling down the barrels, it must be built with the barrels converging towards the muzzle (by a mysterious amount). Because different powder charges, bullet weights, rifle weights, shooter body weights, ambient temperatures, etc., all effect the way a rifle moves under recoil, the only way to balance these factors is by trial and error. This process is called regulation.

The goal of regulation is to make the rifle shoot both barrels to a common point of impact at a range appropriate for the calibre.

One can proceed generally in either of two ways: adjusting the relative position of the barrels or adjusting the load. If one has a fixed load in mind, the former method must be used. It involves repetitive unsoldering and resoldering the barrels until the required convergence is achieved, then relaying the ribs and finally refinishing the barrels.

A simpler method is to vary the load. The longer the bullet spends traveling down the barrel, the greater the force is exerted on the rifle to cause it to move while under recoil. If bullets from the left and right barrels strike the target too far apart at the desired range, and have crossed before they reach the target, the velocity is too great. The bullet weight must therefore be increased or the powder charge decreased. If bullets from the left and right barrels strike the target at the desired range too far apart, but have not crossed before they reach the target, the velocity is too slow. The bullet weight must therefore be decreased or the powder charge increased.

The construction of an effective double rifle is the apogee of the gunmaker's art. If, however, one comes into possession of a double rifle for which the original load is unknown, one can often make it shoot well by adjusting the load to the rifle.

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Because different powder charges, bullet weights, rifle weights, shooter body weights, ambient temperatures, etc., all effect the way a rifle moves under recoil, the only way to balance these factors is by trial and error. This process is called regulation.

I do not believe that this statement is true. Regulation is something that is done by the gun builder, during the manufacturing process to ensure that his chosen load shoots appropriately. He does this by first making sure that the two barrels shoot together at a certain range, and then adjusting the sights so that the point of impact is also the point of aim. Knowing the factory load with which the gun was regulated is very important in handloading for the gun as you know the bullet weight and velocity. Without this information, developing a load is a very time consuming and a very lucky process. In fact if you don't KNOW that the gun was once regulated, you might wind up with one load for the right barrel and a different one for the left! Others more knowledgeable than I will weigh in I am sure. Handloading complicates the process. If you buy a double and know the factory ammo that was used to regulate it, just buy it and you are off to the races. No further "regulation" is required.
Peter.

And then you throw in the fact that it depends on which barrel is fired first because they bend due to the heat of metal expansion, blah, blah, blah....it is a wonder they hit the broad side of a barn.

And what happens when one load shoots to point of aim and the other barrel needs another load? Or they only regulate when a 500 gr. bullet is going 1000 fps? Or it regulates fine at home at 60F but scattters them in the heat at 100F?

If you can get your double regulated, or at least think you have it regulated, praise the Lord and pass the beans.

quote:

Originally posted by 470CapstickA2:
I thought this was a simple explanation of what regulating means, and what factors can play into it...


The goal of regulation is to make the rifle shoot both barrels to a common point of impact at a range appropriate for the calibre.

Most all the post is fact except the last sentence above! The barrels are converged so that the point where the bullet exits the muzzle, of each barrel, the flight paths of each will be paralell to each other, from muzzle till the bullets come to ground down range. The barrels are not regulated to any particular distance, that is done when fileing in the sights, after the regulation is done.

Contrary to popular belief double rifle shooting a proper load DO NOT cross, at any distance. They are regulated to place their individule shots side by side, at the same elevation what ever the range.

The sights are filed in for the range you want your standing rear sight,usually 50 yds, and flip-ups are filed for more elevation, as the range increses, and the windage stays the same regardless of the range.

if you look at the flip-up sights on a double rifle you will see that they are all in line windage wise, and if the load is proper, they will shoot to those sights, at the range engraved on the sight.

If the barrels are shooting a load that is shooting one hole at 50 yds, some think they have a regulating load, and that is absolutely wrong. If the bullets are hitting close enough together at 50Yds to make one hole, they are crossing at 50 yds. with a load like this will be useless with the down range sights, or shooting if no down range sights are fitted, because the bullets will continue to get wider as the range encreases, and is not shooting a proper load.

The Idea that because a barrel set must be converging physically, that they automaticlly cross at some point is understandable, but not true. The lines of sight through the barrels do cross when static, but when fired they move to a point where they are shooting paralell as they exit the muzzle!

You will hear this crossing falicy from very well known rifle smiths, who should know better,and gun writers are notorious for spreading this misconseption. This idea,and those who spread it, are the reason most people do not understand double rifles, or their care and feeding!

Al,
I have a personal bone to pick with the witch doctors that publish this, not you....

quote:

Originally posted by 470CapstickA2:
One cannot build a double rifle, using sophisticated mass-production machinery with barrels perfectly parallel and expect both barrels to shoot to a common point of impact

Yes... nor could one build a double rifle, using ancient english secerts with barrels perfectly parallel and expect both barrels to shoot to a common point of impact

because double rifle barrels aren't perfectly parallel if regulated

as compared to line of sight (i KNOW los has nothing to do with regulation, directly), down the barrels, a perfectly regulated double (let's say it's a 1" 4 shot at 100 gun) the right barrel doesn't aim anywhere NEAR parallel to the left...

parallel ... flat on at least 1 plane, and in this case, 2 .. left/right and up/down.


however, one COULD sample say 10 doubles of the same type and get a dang good idea of where the individual barrels aim (using lasers) and try THAT alignment out on one... if say, 10 searcy's point right to X and left to Y (say a 1/4" circle at 10 yards, chances are that the 11th one, if pointing the same place, will probably be dang close.


Mac,
if I get my 550 flanged regulated to one hole at 50, i am stopping.. that means at 100 yards it would be barely over MOA crossed... and i can live with that

jeffe

Hey guys, aren't you forgetting something?
Not only aren't the barrels parallel, they also aint straight!
The chambers have to be parallel, and perpendicular to the breech face. During regulation and rib-laying, the muzzles are drawn together slightly. Each barrel is therefore curved. It's only the last inch or so before the muzzle that dictates the final direction of the projectile. The convergence angle is dictated by the geometry of the curve.

Not saying this can't be duplicated gun-to-gun with modern techniques, but it's not quite as simple as converging two straight tubes.

It's pretty much what happens today anyway, but there will always be a requirement for final regulation before finishing up, so what would be saved?

quote:

Originally posted by jeffeosso:
however, one COULD sample say 10 doubles of the same type and get a dang good idea of where the individual barrels aim (using lasers) and try THAT alignment out on one... if say, 10 searcy's point right to X and left to Y (say a 1/4" circle at 10 yards, chances are that the 11th one, if pointing the same place, will probably be dang close.

This is exactly what the makers of today do! Over time they have created a formula just as you describe, but it "IS", as you say DANG CLOSE, but not regulated! The ten rifles you say to test all will show a differen LOS picture on a bigineing target, even if all shoot exactly the same on paper, at 50 yds, so the best you can do is place the intial lazer setting at the average between the ten, and what you have is a STARTING POINT for regulation! The regulation from that point must still be done by trial and error,

The formula is only to save time by getting to a close STARTING POINT, then they regulate! That is the problem with many who try to regulate doubles, or work up loads for rifle that are already regulated, they settle for CLOSE, which is an unfinished job. IMO, if you get that close, why not finish what you started? It just doesn't make sense to me to quit the job before it's finished!

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Mac,
if I get my 550 flanged regulated to one hole at 50, i am stopping.. that means at 100 yards it would be barely over MOA crossed... and i can live with that

jeffe

Jeffe, because you can live with that doesn't make it properly regulated! If you only want it done half assed, then regulate to one hole at 50 yds, but I don't see the problem when that close all you need do is move down .5 to 1.0 gr of the powder charge, or with the barrels regulation move the wedge IN less that .070", to make it right!

Where modern machineing like CNC, are a cost savers, is because it saves TIME with the HOG WORK, that, here to fore, was done by shop swampers, with chisles, and files. When an action body is milled from a solid block of steel, by CNC, the shape is the result, but the action body is far from a finished product, and must be finish fitted, and shaped by very skilled artisans. This is where some of the cheaper double rifles save money that makes their product more affordable, to the public, the difference is, the names do not pass this saveings on the the customer.

Normally, even on the cheaper double rifles, the fitting that is critical, like barrels to face, and regulation are done properly, but the outside finish, that is unimportant to the actual opperation of the double rifle, is mediocre at best. That doesn't mean the rifle is not a well made rifle, that will not be servicable for just as long as one made intirely by hand, and decorated nicely, but that is one cause for the difference in price point! Still most of the critical work must be done by hand, and even the so-called cheap double rifles, are expensive when compared to the totally machine made crap like most out of the box K-mart bolt rifles!

Make do is one way to do things, and right is the other, take your choice! What ever floats your boat!

I have shot my scoped 9,3x74R Chapuis on paper at 100,200, and 300 yards. With the loads I shoot the shots do not cross, even at 300 yards.

Tony,
what are you getting for groups at 100,200&300 yrds with your 9.3x74R with the shots not crossing? & what velocities?
The rifle is regulated for I think the Norrma 286 gr loads correct?
How do your loads compare to the factory loads?
Thanks!

Bal I will check my notes when I get home sometime Monday.

My rifle was regulated with the 293gr TUG and iron sights.

It shots good with irons and scope with 286gr bullets.

I do not expect, nor do I try to make it a Sniper rifle.

Bal,
What load are you using for your Chapuis?

ROSCOE,
I have used a variety of different powders & bullets,when I get home tonight I will look them up for you.

NE 450 #2, are you saying that your Chapuis shoot the bullets the same distance apart at all these ranges ie. at 100 yards, 1" apart, same at 200 and same at 300?
Thanks, peter.

When I get back home I will look in my 9,3 rifle book for the info and see if I can find some of my 300 yard targets and give actual measurements.

ROSCOE,
check your pms!