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#240779 08/24/11 06:11 PM
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Greetings All:
I have a Pedersoli Kodiak 45-70 double that I recently bought used. I am trying to find a regulation load for it, but am not having any luck. The individual barrels group well at 100 yards, but the groups are about 8 inches apart at that distance. Changing bullet weights and powder only result in the groups changing vertically, but maintaining the same distance apart. I read that Pedersoli used 300 grain Winchester loads for regulation. I have tried 300, 325, and 350 grain bullets with varying velocities without getting the impact points closer together.
I have read that the impact points will diverge if the velocity is too low, and will cross if too high. Frankly, I am having a hard time getting my head wrapped around this theory. I can see velocity and bullet weights changing impact point vertically, but how do they go side to side?

Thanks, Texas Bill

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Texas Bill,

The "theory" that you speak of as the distance between the left and right shots being influenced by speed has to do with the time that the bullet is still in the barrel and its ultimate direction is being influenced by recoil. In other words once the powder charge is ignited and the bullet is on its way down the barrel the gun has already started recoiling back and up. Along with the upward motion the firing of the right barrel has the gun moving to the right. When shooting the left barrel, of course, it will be moving to the left. The faster the bullet is traveling the less time it is in the barrel and thus influenced by these combined motions. Graeme Wright's book "Shooting the British Double Rifle" is to me a "must have" book for the double rifle shooter as the aforementioned and much more is explained in detail.

Regards,

Buchseman

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Hello Bill,

All double rifles are regulated to group their bullets together at a specific range, usually at a distance under 100 yards. Assuming you are using the same load (Bullet weight and Powder Charge). Double rifles have barrels that diverge and once the bullets are past their regulated distance the left hand barrel will pattern further to the right as the range increases and the right barrel will shoot to the left. Irrespective of what the sights say.

I'd suggest you contact the manufacturer to ascertain the actual loading used and the regulated distance to get both barrels to shoot together.

Harry

Last edited by Harry Eales; 08/26/11 10:16 AM.

Biology is the only science where multiplication can be achieved by division.
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"
The "theory" that you speak of as the distance between the left and right shots being influenced by speed has to do with the time that the bullet is still in the barrel and its ultimate direction is being influenced by recoil. In other words once the powder charge is ignited and the bullet is on its way down the barrel the gun has already started recoiling back and up. Along with the upward motion the firing of the right barrel has the gun moving to the right. When shooting the left barrel, of course, it will be moving to the left. The faster the bullet is traveling the less time it is in the barrel and thus influenced by these combined motions."

Aew there any tests confirming this, or it is just generally accepted theory?

Last edited by Texas Bill; 08/28/11 11:00 PM.
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Texas Bill,

I am not sure how to post pictures and such on this forum so send me a PM and I'll reply with some results of mine from finishing up just such a project this weekend. I reduced a horizontal spread of 2 1/2" down to 1.06" by increasing speed using a combination of an increased charge and reducing the weight of the bullet. I have recently posted these results on another forum but I'd prefer to keep this discussion on Dave's DGS BBS.

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Buchseman

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Texas Bill,

I replied to your PM.

Regards,

Buchseman

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Originally Posted By: Harry Eales
Hello Bill,

All double rifles are regulated to group their bullets together at a specific range, usually at a distance under 100 yards. Assuming you are using the same load (Bullet weight and Powder Charge). Double rifles have barrels that diverge and once the bullets are past their regulated distance the left hand barrel will pattern further to the right as the range increases and the right barrel will shoot to the left. Irrespective of what the sights say.

I'd suggest you contact the manufacturer to ascertain the actual loading used and the regulated distance to get both barrels to shoot together.

Harry


Harry I'm sorry to say the quote above in bold is not true, it is a mistake most all people think is true! The reason is gun writers, and some very well known gunsmiths repeat this misinformation till almost everyone believes it to be true!

The barrels are soldered converging, so the rifle will shoot SIDE BY SIDE to infinity with the regulating load.

If you take the barrels off any double rifle and ploace the underlugs in a padded vice with the barrels suported with the sights aligned on a target at the distance engraved on the rear sight! Then place an empty cartridge in each chamber with no primer, and look through the primer holes like a peep sight, you will see the RIGHT barrel's line of sight will be pointing to a spot that LOW, and LEFT of where the sights are pointing. The LEFT barrel's line of sight will be pointing to a place that is LOW, and RIGHT of where the sights are pointing.

The reason for this is a combination of recoil muzzle flip, and the amount of flip is tied to "BARREL TIME" (the time the bullet is traveling down the bore till it exits the muzzle). If the load is the proper regulating load the bullet will exit the muzzle when that barrel is pointing to a place just on it's own side of the aiming point of the sights. If it is the LEFT barrel it will print just LEFT of the aiming point, and if it is the RIGHT barrel it will print the target just RIGHT of the aiming point of the sights. So if the rifle is regulated properly, and the load you are shooting is the proper load for that regulation the rifle will shoot paralelle no matter the range! The range engraved on the rear sight does not indicate a point where the bullets corss, which they do not, it only indicates the proper elevation for that distance.

This regulation can be badly effected by fireing the rifle resting dirrectly on the sand bags. To find the regulation you need to fire the rifle with only your hands, face and shoulder touching the rifle! You can rest your forehand on the bags but the rifle must be allowed to recoil as if shooting off hand. NEVER EVER use a leadsled to shoot a double rifle! More later because I'm sure you will have something to say about this. One thing that may be wrong with the rifle being questioned here is PEDERSOLI regulated by JIG, and that doesn't work very well! If that is the case the rifle has it's barrels hard brazed, and no smith will re-regulate it, at least one that understands double rifles, Most don't!


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MacD37,
Sir,
I wasn't speaking of theory, for nearly two decades I was the owner of a 577 BP Express double rifle retailed by E.M Reilly and Co, London. It was my experience that both barrels shot small groups together at 70 yards, (their regulation distance). At 100 yards the right barrel was shooting to the left of the POI and the left hand barrel was shooting to the right. The shots were even more widely spaced at 150 and 200 yards. Over the years I put more rounds through that rifle than I care to think about, I still get headaches, thirty years after I sold it.

In any case these large rifle calibres were meant to be stoppers at relatively close range, not long range hunting rifles.

Harry


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Harry I didn't mean to anger you, but you are simply not correct in this case! If the centers of each barrels individual groups from a double rifle is crossing at any distance then the load is not proper for the regulation of the rifle.

Like you I have been in the double rifle business for some time, quite a bit longer than you in fact.I have been hunting, and loading almost exclusively with double rifles for 53 years,since the age of 21 yrs.

I bought my first double rifle in 1958 when I was 21 years old, and have owned over fourty double rifles since that time, and loaded for every one of them except one.

You are correct in that if the rifle is crossing at any range it will diverge more and more from that point down range. However if a double rifle is crossing at any range then the load is not proper for that rifle, close but not proper.

A composite group from a properly regulated double rifle shooting a properly loaded cartridge, that composite group will be slightly egg shaped along the horizontal line thorugh the aiming point on the target. The centers of each barrels individual group will always be on it's own side of the aiming point on the target if properly loaded.

As both barrel's groups go down range they will widen just like any other barrel, so that as the two groups get larger the right shots will spill over into the left group, and the left barrel's group will spill over into the right barrel's group, but he centers of each barrels individual group will remain on it's own side of the aiming point the is in the middle of the composit group!

The missconception that the rifle is supposed to cross is the reason that people claim that the multi filp-up rear sights on a double rifle were put there for decoration only, and nothing could be farther from the truth.

If you look at those flip-ups you will see that the center line of all of them are in a perfect line. If the rifle were supposed to cross the centers of each flip-up couldn't be in line, and would be useless. They were not for decoration but work as they are supposed to if the rifle is shooting properly regulating ammo. An egg shaped composit group of 3 " at 50 yds will still cover an 8 " pattern at 100 yds on a cape buffalo's heart lung at that range, and shooting off hand most will not do better than that with a scoped rifle off hand. At 15 yards to the muzzles of the double they are dead on for stopping. Make no mistake you don't want to stand at 200 yds and let me shoot at you with the largest double rifle I own, hopeing I can't hit you with every shot!

Now none of this is to say a double rifle that is just starting to cross at 50 yds, is not usable that way, it is if you think a double rifle is supposed to do that, and you are willing to accept that type of regulation, but it is not correct regulation! In fact most factory ammo will not regulate properly in most double rifles, but is as good, or better than hand loads that cross!

I'm sure I have not convinced you of anything and that is OK, because as long as your doubles do what YOU want them to do, that is all that matters. Though disagree we may, nothing is lost, we both love double rifles and that is what counts in the long run!

.................. grin Good hunting!


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MacD37,

Sir,
I am not angry at all old chap, it takes an awfull lot more than a minor difference of opinion get me upset. Whilst I bow to your wider experience of Double Rifles, rightly or wrongly I was just reitterating my own experience for Texas Bill.

My .577 BP Express came with the usual folding leaf sights graduated in 50 yard intervals, each with the usual Platignum inlaid centre line, to a distance of 300 yards. Given the calibre and charge I thought that anything over 150 yards was being a little optomistic on the makers behalf, or perhaps it was to try and impress the new owner.

Double rifles I think you'll agree, were designed specifically for game hunting including the most dangerous of wild animals. Now, I contend that a serious sportsman prefers to make one shot clean kills, out of respect for the animal, and I therefore submit that 300 yards, offhand shooting with a .577 is not a sporting shot by any means. You may hit the target, but can you call your shots that accurately for a one shot kill? If not, your not taking a sporting shot in my opinion. Of course more double rifles today are used for punching holes in paper just for the fun of it, than are used in the hunting field. Perhaps that's just as well for the survival of some animal species. Still there's a certain feeling of atavistic nostalgia when handling and/or shooting one of these rifles that just can't be matched by any other weapon.

One thing I would agree on though, is if the chips are down and you have a wounded and dangerous animal at close range and it is coming at you with evil intent, there's not a rifle in the world I rather have in my hands than a Big Bore British made Double.


Harry







Last edited by Harry Eales; 09/11/11 01:25 AM.

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Harry I fully agree with everything you just posted above! However the fact that a 300 yd shot with a BLK 577/450 not being a sporting shot has little to do with the fact that with the 300 yd shot hitting where the sight indicated it will hit, is the point. This is what I was saying the double rifle properly regulated, shooting PROPERLY loaded ammo for the regulation built into the rifle, and with center line of all the sights being in line should tell you that these rifles are NOT regulated to cross shots at any range, and when properly loaded shoot the barrels parallel with the aiming point between the centers of each barrel’s individual groups. Certainly some shots from multiple shots fired at longer range or in fact fairly close range will spill over into the group of the other barrel, because the groups get larger the farther they go down range, as any rifle does. However the centers of each barrel’s individual group remains on it’s own side of the aiming point of the sights.

Loading a double rifle trying to print one ragged hole is not a proper way to load for a double rifle. Simply said, because if they are both hitting one hole, then they are crossing, and by the time they get to 300 yds they will be far apart and the sights would be useless.

Improper regulating loads are the reason most people think a double rifle is useless past the range on the rear sight. Europeans have been using double rifle to hunt mountain game in the alpines for as long as double rifle have been in use. Properly regulated, and double rifle is as accurate as any iron sighted hunting rifle regardless of type! The only difference seems to be that most folks try to apply single barrel technology to a double barreled rifle!

I have a friend that bought his first double rifle chambered for 7x57 Flanged to shoot elk with in Oregon. The rifle had a Quick detach scope in addition to one standing iron for 100 yd and two flip-ups, one for 150 yd, and the last one for 225 yd range He came over to my home saying he had not shot the rifle with the irons, but had simply mounted the scope and tried to zero it in and couldn’t get the rifle to shoot right.

I asked him how he had gone about zeroing the scope to which he replied: “Well I shot the right barrel on the target at 100 yards then adjusted the cross hair over to the bullet hole, as I always do when zeroing a scope. Fired another and the bullet almost hit the same hole cutting it in half ! So far, so good, but when I shot the other barrel it was shooting a little over two inches to the left, so I guess the rifle is not regulated properly or not shooting well with the factory ammo, they said it was regulated with!”

He had made the common mistake most make with double rifles! He tried to use single barrel technology while working with a rifle that had two barrels side by side with the centers of bore one inch apart! He never though about the fact that these two barrels are not going to hit the same hole, and his mistake was not shooting at least two shots, one from each barrel, then adjusting the scope to hit exactly half way between the two bullet holes, then on a new target fire four shots using the same aiming point for all four shots. We did and the rifle was shooting a perfect 2 ½” slightly egg shaped composite group of both barrels at 100 yards. Now all that was needed with to adjust the elevation to place that composite group 2” high at 100 yards, making the point blank range for that rifle holding dead on out to 225 yards, and with a top of the shoulder cross hair to place a bullet in the lungs of an elk at 275 yds.

We later went to a friend’s ranch where he had silhouette range, and placed 8”gong targets at the distances engraved on the irons, and the very satisfying DING, DING, DING sound came from every shot.

Of course that is less likely with a rifle that is chambered for 470NE but it has nothing to do with the regulation, but with the shooter and recoil.


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Hello,

One of the other factors in the theory, is that the CG of the barrels falls in the center of the rib.
The R barrel recoils around the CG which is to the L of the barrel, while the L barrel recoils around the CG that is to the R of the barrel.
Depending of rifeling which may be R handed and L handed per barrel or both R handed, and you see the complexity of the problem.

Cheers
Nitro

PS: Mac knows his stuff.

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