Understanding the regulation of double barrel rifles

Ooops, clicked "post" earlier too fast by accident.
Use only one bullet type, with profile same as originally used to regulate rifle, and later used to re-regulate it by Ken Own. Use only one powder type, R15, unless Ken Owen used a different powder for his regulation load with that given rifle. Don't use 4350 or 4831 no matter where you learned to use them. Don't increase the velocity you shot the 4 inch spread loads with--to increase velocity, all other factors being same, will only increase the spread. Actually, decrease that velocity slightly, hoping for less than 4 inch grouping with left/right barrels. Generally, try to duplicate loads Ken Own used to regulate with, to get same or close to same results as he did.

A "standard" load for the 470 Nitro is either 89 grains of Reloder15 or 106 grains of IMR4831. ...
The IMR 4831 does not require a filler. For the Reloder 15 I stamp a 1" thick piece of foam by 1/2" diameter. Kynoch makes some pre-cut one but they are expensive. Federal 215s are my go to primers, but have used Remington Magnum Rifle with no issues.... Start low on powder charge, use a chronograph. 2150 FPS is the gold standard, but velocity will determine how your rifle regulates. If it is crossing, slow down your velocity. If the spread is too wide speed up.

So, apparently in one experience increasing velocity increases the spread, and in the other experience increasing velocity decreases the spread. I suspect that both persons mean increasing the LOAD, which will have an effect on both pressure and velocity. Likely, the different burn rates and the different charges of Reloader 15 and IMR 4831 cause these opposite results (?) ...

Finicky things these doubles... :)
 
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If the barrels do not shoot to the same point of impact, you have a barrel problem.... not a load, not a cartridge, not a bullet weight, not a speed or whatever problem.

To fix this barrel problem while dealing with cartridges of different load is the attempt of the amateurs with their amateur skills.

It's like to try to start an engine while changing tire pressure.

In the old times, the problem was solved be resoldering the barrels, done by a professional gunsmith.

Today it is done by a muzzle adjustment device ......installed by a professional gunsmith too.

With an modern muzzle adjustment, changing point of impact of the barrels is as easy as zeroing a rifle scope.

You can do it at the range, as often you want, with every load you want, for every distance you want.... with a set of allen keys.

You never will look back.

All thouse who believe, they can do it by changing loads of cartridges, burn money and create stuff for internet forums.

Nothing else....

https://www.africahunting.com/media/double-rifle-range-shoot.75024/

.450/400 2 3/8" double rifle at 100 m


HWL
 
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If the barrels do not shoot to the same point of impact, you have a barrel problem.... not a load, not a cartridge, not a bullet weight, not a speed or whatever problem...
Hmmm...
If you mean it the way you wrote it HWL, then the very concept of a regulation load is irrelevant...
This is not a theory many people subscribe to...

But I do not think that you mean it that way...

Maybe you did not read the thread along and you just looked at the last few post (?). Allow me to clarify that no one is saying in this thread that a double rifle can be regulated simply by changing load parameters. We all know that the only way a double rifle can be regulated is by adjusting mechanically the convergence of the barrels. This was addressed at length in the first page of the thread...

What is being touched upon in the last few posts is not how a double rifle can be regulated by changing loads, but how a double rifle that was regulated mechanically for a specific load reacts when that load is changed by either circumstances (cordite temperature in the old days) or man (different bullets, different powders, different charges, etc.)...

:)

PS: regarding barrel adjustment mechanisms, I am fully aware that they are common (but not universal) in calibers such as 7x65R, 9.3x74R, etc. and even up to .375, but I am not aware that DG stopper calibers (.450/.470/.500 NE etc.) adjustable double rifles are built. I may be misinformed...
 
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So most doubles are regulated for a certain distance, the pro's say if you increase velocity the crossing point is closer, some say further....so I ques if ordering a custom double ask how you want it regulated and with which load/bullet combination...

It also appears that 24" barreled doubles battle to achieve the normal velocity(2150) while 27 " barreled ones do....

I ques for what I want from a double anything within 2 inches inside of 20 yards should be good enough. 500 3 1/4" @ 2250, might as well use custom ammo while at it...if not stick to my 500 Jeff.....

For smaller medium or light bores in a double O/U seems to be the way to go......
 
From another site.....

the left barrel is "pointing" low and right relative to the POA and the right barrel is "pointing" low and left realtive to the POA (thus, the barrels are starting out crossed)

under recoil, the barrels want to move "up and out" away from the centerline (POA)

under recoil, the LB swings up and left, with the bullet exiting when the barrel is parallel to the POA

under recoil, the RB swings up and right, with the bullet exiting when the barrel is parallel to the POA

(the two shots should be theoretically parallel to infinity)

if your load is too slow, the bullet will exit AFTER the barrels pass parallel and the two shots will be wide apart (but not crossed)

if the load is too fast, the bullet will exit BEFORE the barrels pass parallel and the two shots will be wide apart (and crossed)


Remember (!) : the paths are divergent , the distance between the crossed POIs will get greater and greater with increasing range. Crossing is never okay.

draw a box (like below) and map the shots. you need to slightly reduce your charge if they're crossing.
 
Stop stressing..just tell them you want it muzzle distance apart at 65 yards...and you sorted.....and as far as I have seen most big bore double rifles these days and relatively recent past habe 24inch barrels ...i wouldn't have longer...:D Cheers:
 
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I would probably go 26" with the 500 NE.....:D Beers:
 
So based on everything I have read here, the biggest difficulty is that the barrels are off center and therefor must be regulated due to recoil pushing them from side to side. So with an over under, both barrels are on the center line. Shooting either barrel should create a recoil impulse that is back and up and the only difference is going to be the gun's and your body's reaction to recoil that is a couple inches higher for one barrel and lower for the other. I would think that wouldn't be that much of a difference.

So why doesn't anyone make an over-under rifle? Wouldn't it be far cheaper make and easier to regulate?
 
So based on everything I have read here, the biggest difficulty is that the barrels are off center and therefor must be regulated due to recoil pushing them from side to side. So with an over under, both barrels are on the center line. Shooting either barrel should create a recoil impulse that is back and up and the only difference is going to be the gun's and your body's reaction to recoil that is a couple inches higher for one barrel and lower for the other. I would think that wouldn't be that much of a difference.

So why doesn't anyone make an over-under rifle? Wouldn't it be far cheaper make and easier to regulate?
During the golden age (pre WWII) there were more OU rifles made than SxS's. Hoewever, they were made on the Continent - primarily Germany and Austria - not the UK. Several European makers will gladly sell or build you one today. Some, such as Hartmann & Weiss will rival the cost of a new bespoke Holland & Holland Royal. We became fixated on the SxS because American hunters traveled to British colonial Africa initially and were there exposed to the British interpretation of a double rifle. Because Germany lost its African foothold (modern day Tanzania and Namibia) with the end of WWI, their rifle makers concentrated on calibers in OU rifles more suited to European game. The 9.3x74R is a classic from this era. As you surmise, they generally tend to be easier to regulate and much easier to successfully use with an optical sight.

Some will complain that they aren't a good choice for dangerous game because they are slower to reload. I think that is total nonsense. If you own a SxS shot gun and an OU you can quickly prove it for yourself. We have simply come to believe - reinforced by the outdoor writing fraternity - that the SxS is a "proper" double. I am fortunate to own, shoot, and love both.
 
If the barrels do not shoot to the same point of impact, you have a barrel problem.... not a load, not a cartridge, not a bullet weight, not a speed or whatever problem.

To fix this barrel problem while dealing with cartridges of different load is the attempt of the amateurs with their amateur skills.

It's like to try to start an engine while changing tire pressure.

In the old times, the problem was solved be resoldering the barrels, done by a professional gunsmith.

Today it is done by a muzzle adjustment device ......installed by a professional gunsmith too.

With an modern muzzle adjustment, changing point of impact of the barrels is as easy as zeroing a rifle scope.

You can do it at the range, as often you want, with every load you want, for every distance you want.... with a set of allen keys.

You never will look back.

All thouse who believe, they can do it by changing loads of cartridges, burn money and create stuff for internet forums.

Nothing else....

https://www.africahunting.com/media/double-rifle-range-shoot.75024/

.450/400 2 3/8" double rifle at 100 m


HWL
Well no actually - that isn't precisely correct. Certainly not with vintage rifles. When dealing with a rifle made during the golden age prior to WWII and perhaps just after, it is impossible to obtain a box of the rounds that were used to regulate it originally - unless you have a working relationship with H.G. Wells. The rifles, however, give us hints - often the bullet weight is clearly marked giving the reloader a good starting point (we can guess at the likely bullet configuration based upon the manufacturer of the rifle). Because enthusiasts have been playing with these treasures for a couple of decades now, we have a good idea which current production powders, fillers, and bullets are most likely to duplicate original regulation performance. It is a rare unmolested rifle that won't give up its secrets with just a bit of work at the bench. I say unmolested, because too many of these guns have seen the ham handed efforts of shade tree gunsmiths, or the rifles have loose ribs, or even barrel solder - all of which can affect regulation. If I owned a nice condition Westley Richards from the thirties, the last thing I would want someone to do is start sawing away at the rib to install a mechanical "regulator". The next owner would be sure to appreciate it as well.

Now if I had a relatively modern, middle grade rifle, of limited collector value, that wouldn't shoot - I have one now by some French fellows - such a device might be a good investment to improve on sloppy regulation by the manufacturer.
 
During the golden age (pre WWII) there were more OU rifles made than SxS's. Hoewever, they were made on the Continent - primarily Germany and Austria - not the UK. Several European makers will gladly sell or build you one today. Some, such as Hartmann & Weiss will rival the cost of a new bespoke Holland & Holland Royal. We became fixated on the SxS because American hunters traveled to British colonial Africa initially and were there exposed to the British interpretation of a double rifle. Because Germany lost its African foothold (modern day Tanzania and Namibia) with the end of WWI, their rifle makers concentrated on calibers in OU rifles more suited to European game. The 9.3x74R is a classic from this era. As you surmise, they generally tend to be easier to regulate and much easier to successfully use with an optical sight.

Some will complain that they aren't a good choice for dangerous game because they are slower to reload. I think that is total nonsense. If you own a SxS shot gun and an OU you can quickly prove it for yourself. We have simply come to believe - reinforced by the outdoor writing fraternity - that the SxS is a "proper" double. I am fortunate to own, shoot, and love both.
This is 100 % true , sir . In the 1960s , over under double barreled rifles were extremely popular among my continental clients , and they were almost always made in 9.3 × 74 Rimmed or 7 × 57 Rimmed .
I have also seen a dozen or so , over under double barreled rifles chambered in .458 Winchester magnum ( but these were plagued with extracting issues ) .
I found the works of the gun makers of Ferlach ( Austria ) to be quite fine ... among them Franz Sodia being my personal favorite . They did have a tendency to put automatic safeties in their wares though ( which was a feature that l did not like so much , on dangerous game double barreled rifles ) .
The only English over under double barreled rifle , which l had ever seen in my career was made by a company named " Boss & Co. " . It was a .375 Holland & Holland magnum calibre , regulated for Dynamit Nobel ( RWS ) ammunition .
 
This is 100 % true , sir . In the 1960s , over under double barreled rifles were extremely popular among my continental clients , and they were almost always made in 9.3 × 47 Rimmed or 7 × 57 Rimmed .
I have also seen a dozen or so , over under double barreled rifles chambered in .458 Winchester magnum ( but these were plagued with extracting issues ) .
I found the works of the gun makers of Ferlach ( Austria ) to be quite fine ... among them Franz Sodia being my personal favorite . They did have a tendency to put automatic safeties in their wares though ( which was a feature that l did not like so much , on dangerous game double barreled rifles ) .
The only English over under double barreled rifle , which l had ever seen in my career was made by a company named " Boss & Co. " . It was a .375 Holland & Holland magnum calibre , regulated for Dynamit Nobel ( RWS ) ammunition .
That Boss, wherever it is, would bring a fortune at auction today. Boss makes a magnificent bespoke OU shotgun that commands huge prices on the shooting and collector's market. https://bossguns.com/ Boss never made a "production" anything - all are to order - "Best Guns Only" as their motto says. As rare as their OU shotgun is, an express rifle would represent a tiny proportion of those made. https://www.theexplora.com/boss-co-over-and-under-500-3ne/ This is a .500. I am envious. I have never actually seen one.
 

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All this reading about regulation, POA, POI has reaffirmed one thing for me.
The only break action rifle I'm likely to buy is a Kipplauf.

My complements to those of you skilled enough to shoot a double rifle well.
 
Thanks BeeMaa. I do shoot a double rifle well but only after some 1 on 1 instructions from my PH who visited me in CT and a lot of practice both off sticks and by doing "run and gun" exercizes on multiple targets. My Krieghoff Classic in .470 NE was regulated at 50m in 2006 using Federal 500gr "Wood" which I assume means "Woodleigh". I do not know what the velocity of the 2006 Federal loads was. I purchased 80 rounds of Nosler Safari 500gr solids (2100 fps) and these shoot to the desired POI. I also shoot Federal Premium Safari Cape Shok in the new 500gr Woodleigh Hydro Solid (2050fps) well but not as tight. I prefer to have the initial shots at game be Swift AFrame and I am reloading these in the spent brass. I reloaded these with IMR8431 at 1999fps but the shots are spreading out. I hope that switching to RL25 at 2092fps will help. Any input on this matter is greatly appreciated. Ed
 
you want the two barrels to shoot together? OK but first you have to know which barrel is the LEAST accurate because that's the best its going to do no matter what, so shoot both barrals separately for group ( here you are actually dealing with 2 guns) when you determine the most inaccurate barrel your that's your goal, nothing to do with crossing or spreading … So now you can with loading move that POI only an inch or two with the sights....the sighted in double is in its regulation...If your shooting your own loads you wasting your time....Again find out the regualation load from the maker and use it or have the gun re-regulated to a specific load..Its not a bolt action te sights just won't do it.
 
"Acceptable results equate to an inch and a half at 65 yards. Some people prefer a longer distance these days, especially boar hunters, who often want the rifle regulated to one hundred yards. The regulation distance is important. For example, a rifle regulated to touch bullets at fifty yards will be crossing at seventy; meaning the right barrel’s bullet will impact to the left of the left barrel’s bullet. Barrels regulated, as Keith prefers, to shoot within and inch and a half of each other at sixty five yards, won’t start to cross until they reach a hundred yards."
from the article on page 1.
 
What I see most of the time is so many folks equate "Regulation" with "Sighting In", not the dase at all..Regulation is the procedure of pullin and pushing the barrels together with a shim then tieing with wire, test fire with a specific load to shoot center at 50 yards or whatever, when the shot come together you solder then barrels together and your done and your sighted in. The gun may not shoot to exactly the same POI for you as it did the regulater, so you can use the sight adjustment and/or tinkering with the powder charge or bullet a bit to fine tune a double...but this can be tricky or rather confusing..Keep in mind that a double is ready to shoot out of the box and it works for most that way, but a double will only work with the one load that it was regulated with..The world of the double is a nuther world, has nada to do with the world of other firearms, I have only touched on the subject, and tried to explain it in a paragraph , and that's hard to do..It one double does not shoot to zero, then contact a good double gun gunsmith and don't tinker with different bullets powder or loads for the most part..
 
Doubles are not meant to be tack drivers, period. If you cant take a bit of convergence or divergence, go single barrel.
HOWEVER, electronics may have a simple answer to improving regulation. The answer is to have a sight that instantly changes ever so slightly to be ideal for the left or the right barrel. The modern reflex sight could be set up with two light sources that switch across depending upon which barrel is in use, always front trigger first, back second. You would zero on the range with presumably screw adjustments on each side.
 
Explaining "barrels regulation"...

Let me give it a shot (pun fully intended) :)

The two barrels should shoot together, right? Whether "together" means shots touching, 1" apart, 2" apart, etc. can be discussed endlessly, but it seems that for DG hunting out to 50 meters/yards with iron sights, 2" groups are OK.

On DG doubles built for .500 case-head (that includes most .400, .450, .465, .470, .475, .476, .500), the two barrels are about 1" apart, bore center to bore center, at the breech, so one would think that if they stayed parallel, 1" apart, bore center to bore center, all the way to the muzzle, the two barrels would shoot parallel into eternity, right?

That is almost, but not quite 100% true with the over/under rifles because both barrels recoil in the same vertical axis as the rifle stock grip, and almost the same vertical axis as the stock (depending on stock cast). Therefore, recoil is essentially in straight line and there is no sideways yaw. This is why O/U doubles rifles are easier and cheaper to make, and much less sensitive to ammo variations (bullet weight, bullet bearing surface, velocity, etc.), and when changing ammo with them, most of the changes are addressed with replacing the front sight to move the point of impact (POI) higher or lower to the point of aim (POA).

Where the side by side doubles are different, and the bigger the caliber, the more pronounced the difference, is that neither barrel is in the same vertical axis as the stock grip and stock. The left barrel is left of the stock, and the right barrel is right of the stock. What this means is that the left barrel pulls the rifle left under recoil, and the right barrel pulls the rifle right under recoil. This is the "yaw." The two shots diverge under recoil. Always. How much to the left and to the right? It depends how long the bullets take to go through the barrels (bearing surfaces, velocity, barrels length, etc.), hence how long the recoil lasts, and how much recoil and yaw there is (caliber, bullet weight, velocity, powder charge, etc.).

The only way to get the two shots "together" is for the two barrels to mechanically converge when assembled. The typical .470 will have about 1" distance bore center to bore center at the breach, and about 0.75" distance bore center to bore center at the muzzle. The barrels clearly converge. This is an easy-to-verify fact.

The art of barrels regulation is to have the two barrels converge just enough when soldering the front wedge between them, so that the convergence of the barrels compensates exactly for the divergence of the shots under recoil. In a perfect world, the barrels convergence at the muzzle would be just so, and the rifle would shoot two parallel trajectories and the two shots would never cross nor spread.

This would be the ideal world, but this is not the real world, if only due to the fact that no two shooters get the same group from the same rifle, because no two shooters control recoil exactly the same way and keep the rifle from yawing left then right exactly the same way.

In the real world, the process of barrels regulation means soldering the front wedge between the barrels/shooting/unsoldering and moving the wedge/resoldering the wedge;
... and again shooting/unsoldering and moving the wedge/resoldering the wedge;
... and again shooting/unsoldering and moving the wedge/resoldering the wedge;
... and again, and again, etc. until the result is deemed good enough.
Good enough is not the same for each gunmaker. Good enough is when the gunmaker meets his goal (whichever that goal might be) and calls it quit. The less expensive the double, the faster this time comes. Push time savings - understand: costs savings - to its limit, and some makers try to replace the "solder/shoot/unsolder" process with blind soldering of a CNC machined wedge, and there is no predicting what group size the rifle will shoot, and where it will shoot it. Enter the infamous Dremel to start altering the crowns and push bullets right or left as they leave the barrels...

The really good regulators get the barrels close to shooting parallel, but very rarely do they shoot perfectly parallel, so all doubles will tend to cross (at 50 meter/yard? 75? etc.) or they will tend to spread (1" group at 25 meter/yard, 2" at 50? 3" at 75? etc.). This is just the nature of the beast. And that is the day the rifle was regulated, with the ammo lot used, and with the shooter used... Then the sights are adjusted so that the point of impact (POI) covers the point of aim (POA).

Now, add to that, even when shooting the exact same bullet with which the rifle was regulated, some differences in powder lots, temperature of the place (Africa vs England or Germany), barometric pressure (altitude), humidity, shooter form, shooter's ability to control recoil and yaw, shooter fighting the recoil or rolling with the recoil, etc. and most doubles fired by most shooters will not shoot parallel and their shots will either converge or diverge.

In the old days, the British gunmakers regulated their doubles to cross at 50 to 65 yards in England because cordite developed higher pressure in warm Africa than in cold England, so when the rifles were shot in Africa, the higher pressure caused more recoil. More recoil caused more yaw and divergence when shooting, and the crossing at 50 to 65 yards either moved to 100 yards, or maybe was replaced by spreading at 100 yd, which was fine enough for any real world application.

In the old days too, the British gunmakers also insisted that the rifle be shot during regulation by the client himself, so that the clients's unique way of controlling recoil and yaw would be built into the regulation. When they built for clients with considerable experience (e.g. professional ivory hunters) they built a little less convergence into the regulation because these guys knew how to control recoil and yaw. Conversely, rifles for first time safari clients usually had a tad more convergence, because it was likely that the rifles would yaw a little more under recoil.

So, in summary, there is no hard rule for what is regulation of double rifles, because the results will change with the same rifle shooting differently for different shooters, even with the same load. Never mind with different loads. In the real world, a rifle is very well regulated in my view when it keeps 2 shots from each barrel of its regulation load in a 2" group anywhere between the muzzle and 50 yards. And, realistically, 3" is OK too in my view. Whether this group at 50 yd has the two left shots on the left of the group (no crossing - preferable) or on the right of the group (crossing likely around 40 yd and starting to spread at 50 yd - less desirable), is essentially OK too as long as one does not try to group this rifle at 100 yd. And this will change when the shooter changes bullet shape, load, powder lot...

Developing the loads a fraction of a grain at a time to increase or decrease the amount of yaw (recoil energy) and the time the bullet spend in the barrel (velocity) will increase or decrease the divergence of the shots between recoil, and will bring the rifle into the convergence built into the way the wedge was soldered.

Sorry, this is again probably too long of a post, but this is not an easy subject to compress into just a few sentences...

I hope this answered the questions :)
One day and everyone. My new 470 NE has 85.5 grains of RL 15 shooting 500 grain bullets. With my red dot sited in, the right barrel places my shot at 50 yards perfectly in the bulls eye. My left shot absolutely crosses over the right landing on the right side of the bullseye 2-3 inches wide. I have checked this three times. Here is my question...if I do not want my left barrel to cross at 50 yards, do I reduce my powder charge to stop this until I get my desired 2 inches of regulation or better?

Much appreciated!!!!!
 

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