No doubt everyone interested in doubles sooner or later learns the usual explanation how it is that a double rifle with barrels mechanically set to converge in fact shoots parallel. That explanation is recoil not acting in line with the centre of stock turning the gun to the side when being fired.

I admit it always sounded implausible to me that this is the reason for the double to shoot parallel. Then I found this 19th century article written by a very reputable person. For those who know what "Field" trials are I'll say the author was responsible for collating all data from it and carrying many experiments.

Here is the article (sorry for quality, it is a 130 year old reprint).



Hopefully it is readable. I started another thread about it on muzzleloading forum as this is my main interest in doubles, but I thought it is important to inform those that haven't seen this article a much better explanation than "recoil" exists for why doubles shoot the way they do!

It looks to be an interesting article, but it us not clear enough for my old eyes to read.

Is it possible for you to provide the name of the book from which you copied this article?

Yes, of course. Originally it was published in a magazine called "Field" in 1st of December 1888.I copied it from a book of public domain reprints titled 'Sporting Guns and Gunpowders, Comprising a Selection From Reports of Experiments, and Other Articles Published in the "Field" Newspaper, Relative to Firearms and Explosives, Volumes 1-2' compiled by Frederick Tom's. Pages 90-91.

I'll copy a summary I posted elsewhere below.

It is a report of experiments carried out.
They attached a set of parallel barrels (with ribs soldered in usual way) in way shown on picture no 1 that prevents them moving to a large block of wood. They used steel straps and screws to hold barrels to the block of wood by breech.They backed the block of wood to prevent recoil. They shot this contraption and it was determined it shoots 20 inches wide at 100m. No recoil movement possible, and yet it does shoot wide.

They desoldered the barrels and resoldered them as they originally were (with adequate convergence of barrels). The attached those barrels to the same block of immovable wood. Barrels shot well (no divergence as if they were shot by hand).

Then they installed another normal set of double rifle barrels in a cross-eye stock. This is a kind of stock made for people with right hand and left eye dominant. It has a very large bend in the wrist so one can use left eye to aim. They expected that if the recoil principle is correct it would shoot left. It was shooting normally.

Finally they took a set of double barrels. Plugged the muzzles and subjected them to high pressure liquid. They noticed the liquid stretches the steel to increase the diameter of the barrel being "fired". At the same time as diameter increases the length becomes very slightly shorter as happens in any pipe under immense pressure. As this barrel is attached to another the whole contraption bends to the side. They(and I) think this hydrostatic part of the experiment well emulates what happens in a set of double barrels when they are fired.

I hope this helps.

Interesting article and idea.
However I doubt the tie-down measures used (steels traps and screws,,large blocks of wood) could absolutely elliminate any recoil of the assembly.
It could for all the world appear immovable. but a mere few .000 deflection can certainly effect bullet impact especially at 100m.
Even the sturdiest assembly with modern clamping and bolt up when a dial indicator is placed on it can generally be shown to deflect with finger pressure if enough leverage is allowed.

The bbl does move from recoil before the bullet exits the muzzle.

Recoil is a physics force. It is there and has to go somewhere. You can't make it disappear with clamps, blocks, straps and screws.
It's effect may be deflected in some way or direction changed, but it can't be dismissed.

Just my thoughts
Nothing more than that.

I enjoyed the article. Thank you for posting it.

Regulating a set of bbl's will always be somewhat of a mystery. Some will set in w/o much of a problem at all. Another set may battle and seem not to want to follow any rule or reason. So many variables involved way beyond the bbls themselves.

I can't read the article either. However the conclusion that recoil, projectile in barrel time, and muzzle flip do not all contribute to how a double RIFLE shoots, is complete nonsense.
We know this from all our/your collective experiences, but I also know it from extensive testing done on tank cannon barrels; the results of which are classified; suffice it to say that recoil and muzzle flip/jump definitely determine where the projectile is going to go.
So, with a somewhat lighter platform than a tank recoil mechanism, how we hold them makes a big difference in how they shoot as well.
So, the article, is not to be believed. In my opinion, and that of many others. Not an opinion actually.

quote:

Originally posted by dpcd:
I can't read the article either. However the conclusion that recoil, projectile in barrel time, and muzzle flip do not all contribute to how a double RIFLE shoots, is complete nonsense.
We know this from all our/your collective experiences, but I also know it from extensive testing done on tank cannon barrels; the results of which are classified; suffice it to say that recoil and muzzle flip/jump definitely determine where the projectile is going to go.
So, with a somewhat lighter platform than a tank recoil mechanism, how we hold them makes a big difference in how they shoot as well.
So, the article, is not to be believed. In my opinion, and that of many others. Not an opinion actually.

Absolutely! regulation of a double rifle is a complex undertaking, and few here seem to understand it's propensities to scatter groups all over the target because of only one or two grains of powder difference in a load, or the addition of simply adding a scope to the rifle.
These two things change the rifle lifts, and moves the muzzles of the rifle while the bullet is traveling down the tube before it exits the muzzle.
On top of all this, the way one holds the rifle is also a real important fact when regulation is a problem when a double rifle suddenly starts scattering shots on the target.
These are the reason some folks simply cannot understand why the changing anything from a load to a different bullet weight, or different powder charge that the rifle doesn't regulate any longer.
.................... MacD37

I'll add to MacD37 that Changing a recoil pad, installing a Red Dot or worse yet a scope can all change POA/POI...

quote:

Originally posted by dpcd:
I can't read the article either. However the conclusion that recoil, projectile in barrel time, and muzzle flip do not all contribute to how a double RIFLE shoots, is complete nonsense.
[...]
So, the article, is not to be believed. In my opinion, and that of many others. Not an opinion actually.

The images are very high resolution. They can be magnified on any device you use to read the forum. Then it will be easier to read. As you didn't read the article your conclusion can only be based on my very short (and possibly flawed) summary. If you are interested enough I suggest you try magnifying it. If I have time later and people still can't read it I may be able to retype it.

Coming back to the topic. Neither I nor the article say anywhere recoil doesn't act at all on a set of double barrels (as it acts on any gun). All that is claimed by me is that the main reason for the majority of the deflection is barell steel stretching as described not recoil moving the whole gun. The article doesn't make any claims. It is simply a report of experiments made and results. Conclusions are left for the reader to make.

As another person said. It is not possible to completely eliminate recoil even by bolting it to an immovable block of wood, but it certainly is possible to severely limit recoil force effects comparing off hand vs immovable block of wood as described. If a set of barrels regulated to shoot parallel off hand continues to shoot (very close to) parallel attached to that block of wood it has to be something else than recoil that is responsible for the majority of the effect. If it was recoil we would see points of impact crossing.

"All that is claimed by me is that the main reason for the majority of the deflection is barell steel stretching as described not recoil moving the whole gun. The article doesn't make any claims. It is simply a report of experiments made and results. Conclusions are left for the reader to make. "

I read the article. It and it's conclusions are sheer Nonsense. Complete and utter nonsense. Definitely not borne out in any modern day practical experiences. By anyone.

quote:

Originally posted by dpcd:
I read the article. It and it's conclusions are sheer Nonsense. Complete and utter nonsense. Definitely not borne out in any modern day practical experiences. By anyone.

I would be very interested to read a record of those modern day practical experiences with double rifles. Unless they are classified of course or you are extrapolating from experiences with single barreled guns in which case you're missing a huge extra variable. Namely the other barrel soldered to the first one along its length :-)

BTW, I would love to learn about any modern military equipment that even remotely approximates the shooting characteristics of a double barreled rifle(with barrels joined along the whole length).

Interesting idea. Does anyone make a SxS double without a top and bottom rib, i.e. the barrels just float with respect to each other? I believe there are some OxU rifles being made this way. It would be easy to see if the barrels on these are positioned to 'converge' rather than run parallel.
C.G.B.

Lukasz,

Thanks for posting the article. Very interesting. I hope you don't take offense that folks don't reject the current recoil and projectile time in barrel double rifle regulation ideas.

I imagine you've read Graeme Wright's 'Shooting the British Double Rifle'. If not, it's a good modern source on reloading for double rifles and loading to regulate them, based on the idea of recoil and projectile time in barrel(s).

While I really like the article you've provided, I think the recoil-based explanation accounts for the fact that there's a vertical component to the POI offset that you can adjust for with reloading. This has proven true for me in a very small sample size, but Wright also documents this across a number of rifles, and as DPCD has indicated, it's been widely tested and documented. I get your point about the double rifle potentially being a different type of system, but the recoil/dwell time affect on the system can't have vanished or have been entirely eliminated in the testing.

I think I remember reading that some folks believe there's also heat transfer and that accounts for sometimes different second shot placement if the second shot is more than a few seconds after the first shot. I haven't noticed this myself, but I haven't really done any testing either.

I sure notice the recoil/projectile dwell time in barrel effect with handguns, and even shooting precision rifles off of bags, and seeing the difference with and without a muzzle brake. I think it's too noticeable and repeatable to be dismissed as a myth.

To answer your questions to me;
1. My and many other's, experience is with Double rifles, all behaving as Skl has explained above. Two side by side barrels, and not necessarily soldered together.
2. The very idea of barrel stretching is what causes Double Rifles to respond as they do, is ludicrous. I just don't believe that 19th century test is valid.
3. With regard to my comment on tank cannon shot placement based on muzzle flip and jump; yes of course, those are single barrels. Mentioned only to say that that phenomena has been seriously proven and documented. Add another barrel to the equation and the variables triple in importance.
But one of them is not from the barrels stretching.
If that were true, then why does adding any little variable to the rifle, make them shoot entirely differently?
I have build double rifles, and they are very sensitive to many things as already mentioned. Even the way you hold them will affect shot placement for each barrel.
Intersting article; maybe only applicable to black powder cartridges fired in wrought iron barrels. The 500 BPE is what they used.
Mr Lucas; it is not personal; just that there is a lot more to how and why double rifles act as they do.

Also, to address Mr Cgbach's question; are there any DRs that do not have the barrels soldered together? Definitely and I have two of them and have owned several more;
The Baikal and the new Chapuis with adjustable regulation, both side by sides. They have barrels that are not soldered together; they are allowed to be bent by adjusting screws; They definitely converge and react just like any other conventional double rifle, only they are much more accurate because you can tune them to your ammo, scope, method of holding, etc. Barrels can't be parallel; that won't work, except maybe on a 22 LR. Never had one.
I have also built 9.3 double rifles on which the ribs were not soldered on; the barrels float, except at the breech and muzzle; same reaction.
So, it ain't the ribs either.

DPCD is 100% correct.

I had a very demonstrable experience with how muzzle flip, time in the barrel, affects double rifle regulation when I added a 1.25x4 Trijicon scope to my Chapuis 9.3x74R.

That rifle will shoot anything you feed it while using factory irons. Put the scope on and you get a MAJOR change in how the gun shoots.

I forget how may loads I went through to arrive at a solution that would shoot both barrels roughly parallel out at distance. I believe it was 11 load combinations. Others have scoped the same make / model / caliber of this rifle with no problems but my particular rifle was a beast to tame in this manner.

There was no "barrel stretching" involved. Only the fact that adding weight to the top of the rifle completely changed the movement of the gun under recoil and therefore changed the gun's regulation. The scope was mounted with a quick detach so take it off, and it shoots fine. Put it on and it's a one load gun. And when I say the scope affected the regulation, I don't mean a little. For instance, 286gr TSX bullets shot about 1/2 inch apart at 50 yards without the scope. With the scope, they crossed 12". Didn't matter what powder I used ... same result. I finally settled on the CEB Safari Raptors and solids. Even though those 2 are of different weights, the gun will shoot those fine, WITH THE CORRECT POWDER AND FILLER ONLY.

Having now regulated over 100 double rifles, some of which were Damascus barreled guns…the article is another mental masturbation piece that defy my personal experiences.

quote:

Originally posted by Aaron Little:
Having now regulated over 100 double rifles, some of which were Damascus barreled guns…the article is another mental masturbation piece that defy my personal experiences.

Thank you

quote:

Originally posted by Aaron Little:
Having now regulated over 100 double rifles, some of which were Damascus barreled guns…the article is another mental masturbation piece that defy my personal experiences.

Aaron,

This is a great big "Like" to your reply above!

I don't claim to know about regulating a double rifle but I know about loading for and shooting long range rifles. Anything one changes from powder, bullet seating depth and crimp tension, and shooter's position can change the POI and/or the accuracy (group size). Consistency is the key! A pair of shooters with identical precision made rifles may require different loads to achieve the accuracy required.

Now, compound any of the above with two side by side affixed barrels and the problem of accuracy combined with the same POI at a given range is at least one order of magnitude more difficult.

No offence taken. When posting something challenging established knowledge one has to be ready for some critique.

I think the vertical component as skl1 mentioned is a very valid point against this hypothesis as well as the same effect with barrels floating (mentioned by dpcd).

But, how to explain the results of the experiment? Aaron Little, I'm not trying to belittle your actual experience building those rifles, but calling it mental masturbation dismisses it as if the author came with the idea beforehand and maybe tweaked his setup until he got the results he was after. Is it possible that happened? Sure, everything is possible, but it would be very strange for him to risk his good reputation for something like that.

Regarding actual alternate explanation of the experiment I can accept the whole "cross-eyed" stock part is dodgy as a good shooter could possibly adjust the body position to compensate.

Similarly with the liquid pressurisation of barrels. No pressure used was given and no precise location in the barrels stated.

However, that first part with the block of wood is interesting. Perhaps someone will one day repeat this properly (using reinforced concrete not wood, with a high speed camera etc).

I'm not going to argue for or against any particular conclusion. I myself haven't performed those experiments so I can't vouch for them of course.

I forgot to answer skl1 about the "Shooting the british double rifle" by Graeme Wright. I looked for it for quite a while. When I saw it it was 400 EUR(then it went quickly) which seemed quite steep especially that it seems focused on modern cartridge reloading while I'm mostly interested in muzzleloading doubles. If I ever find it for around 200 EUR I'll probably buy it.

quote:

Originally posted by Lukasz:
No offence taken. When posting something challenging established knowledge one has to be ready for some critique.

Yes, that is often the case when presenting NEW information challenging established knowledge. But this report you are presenting was, as best as I can tell, put forth in 1888. There has been a lot of study and work put into the development of double rifles since that time.

Take for example, The Double Rifle Bullet of the Future thread here on AR. Michael and Sam presented a plethora of NEW evidence from NEW experiments in trying to determine which bullet designs are safest on double rifle barrels. Much of their NEW evidence challenged OLD perceptions and they had to go to great lengths to defend their methods.

What you are presenting is just the opposite. You're trying to push an OLD theory that has been proven to not hold water with the years of experience since it was published.

I'll put it in real life terms again. If not for barrel travel both in the vertical and horizontal planes affecting double rifle regulation, how do you explain my Chapuis 9.3 shooting every load fed it perfectly to regulation without the scope, but putting all that weight on top of the barrels suddenly makes some loads cross badly while others do not come close to each other? Take the scope off and the same loads go right back to regulation.

It took a specific load, meaning projectile weight, shape, velocity, and acceleration rate to reach that velocity, in order to get the bullet to leave the respective barrels at the exact right time in the recoil arc in order to strike the target approximately 1" apart at 50 yards. The addition of the scope didn't have any affect on "barrel stretching". It was purely and without question, weight that changed the recoil arc of the two respective barrels.

Right; barrel stretching, even if it is real, cannot possibly account for all the vagaries of double rifles.
Anyway, we do know, or at least have a good idea, of the pressure of the cartridges used in the 1880 "test". For a 500 BPE, using a 440 grain bullet and a 136 grain charge, the pressure is 11 tons. More or less.

quote:

Originally posted by Todd Williams:

quote:

Originally posted by Lukasz:
No offence taken. When posting something challenging established knowledge one has to be ready for some critique.

Yes, that is often the case when presenting NEW information challenging established knowledge. But this report you are presenting was, as best as I can tell, put forth in 1888. There has been a lot of study and work put into the development of double rifles since that time.

Take for example, The Double Rifle Bullet of the Future thread here on AR. Michael and Sam presented a plethora of NEW evidence from NEW experiments in trying to determine which bullet designs are safest on double rifle barrels. Much of their NEW evidence challenged OLD perceptions and they had to go to great lengths to defend their methods.

What you are presenting is just the opposite. You're trying to push an OLD theory that has been proven to not hold water with the years of experience since it was published.

I'll put it in real life terms again. If not for barrel travel both in the vertical and horizontal planes affecting double rifle regulation, how do you explain my Chapuis 9.3 shooting every load fed it perfectly to regulation without the scope, but putting all that weight on top of the barrels suddenly makes some loads cross badly while others do not come close to each other? Take the scope off and the same loads go right back to regulation.

It took a specific load, meaning projectile weight, shape, velocity, and acceleration rate to reach that velocity, in order to get the bullet to leave the respective barrels at the exact right time in the recoil arc in order to strike the target approximately 1" apart at 50 yards. The addition of the scope didn't have any affect on "barrel stretching". It was purely and without question, weight that changed the recoil arc of the two respective barrels.

Todd is correct about the weight of the scope and mounts having an ill effect on the regulation. The fact is not only the weight of the scope and mounts, but the difference in the height above the barrel set of that weight above the barrels also causes a difference in regulation as well.
I had a double rifle chambered for 45-70 that regulated perfectly, with my 45-70 loads. I made the mistake of re-chambering that rifle a wild cat known as 458 RCBS and today after trying every load known to man that rifle still is lucky to place both barrels on a wide side of a barn and will have to be re-regulated for that load if I ever use it again. However, I'm thinking about having a set of barrels for 450-400NE stubbed into the barrel butts and regulated by Aaron Little.
Anyone who doesn't believe adding or lowering of weight to a double rifle will not cause the de-regulation of holes in the target is in for a surprise. and I predict not a good surprise.

............................ MacD37 '

PLus 1 on MacD37,

Im of the school of double rifles that finds the one regulated load, and stick with it..If I need to prank around I will do that with a bolt gun or even a lever gun, but do not touch my double except to kill something big and mean, and with iron sights at under 150 yards with a specific load in both a soft and a solid, and even that can be a chore, but once done, put it up..Just my 2 bits..