Understanding the regulation of double barrel rifles

One Day...

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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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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.

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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One Day...

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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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spike.t

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IvW

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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......
 

IvW

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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.
 

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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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IvW

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I would probably go 26" with the 500 NE.....:D Beers:
 

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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?
 

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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.
 

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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
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.
 

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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 .
 

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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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BeeMaa

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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.
 

Ed Lally

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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
 

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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.
 

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"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.
 

RayAtkinson

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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..
 

Kevin Peacocke

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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.
 

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