I have a browning o/u 30-06 double rifle that was just regulated for Hornaday 165 ammo after a custom quarter rib and scope mounts was added the problem is that with a scope added the gun shoots outstanding (1.2 to 1.4 inch groups) but with the scope off they state that the gun crosses at fifty yards three inches, has anyone had problem like this? Note I only plan to use the scope that was the reason I have spent over 4000.oo in quarter rib and Zeiss Veripoint scope plus regulation. But I thought it was weird that this would happen.

Sometimes a scope will effect regulation.

However you might find that the rifle will shoot OK with the iron sights with a different weight bullet.

Also you may find that the way you hold the rifle when shooting from hunting positions, it does not cross that much with your 165gr load...

Or you may find it cressed more.

You will just have to give it a test to see.

rnb,

A scope is one sighting system, iron sights another. If your 165 grain load shoots lights out in your DR with the scope, theoretically, with properly adjusted iron sights you'll get the same results. All depends on the ability of the shooter.

The gun doesn't know which system you're using.

I was told by several shooters that adding the 19 0z scope will change the barrel harmonics and that is why it changes impact points but as long as it shoots into a quarter with its scope, I guess I shouldn't care, I wish I could have everthing but if forced to use the iron sights at my age the animal will probley have powder burns anyway because I would have to get very close be sure of a clean shot and the rifle is more than capable of doing that, but with the choice of either iron sights shooting to point of aim or the scope doing so I will choose the scope anytime.

You are correct, adding a scope can change the barrel harmonics.

As others have said, changing the bullet weight may help with the open sights.

The rule of thumb with a side by side would be to reduce your load if they are crossing. I have found this to not be allways true with an O/U rifle.

Like N E 450 No2 said check the way you hold your rifle. My first double rifle was an O/U Merkel. It shot great from the bench and it did not fail me in the fieald but after reading the knowledgeable words from the guys hear at AR I decided to check my rifle from a standing bench.

All I can say is that if your barrels pulled apart as much as mine did your problems would be solved.

RNB, the word Harmonics is a misnomer where double rifles are concerned. Harmonics in rifles barrels is a set of waves the run the length the barrel as the bullet passes through the bore and places the muzzle at a point when the bullet exits, effecting the POI.

In the double rifle the barrels are tied together and are very stiff, and rather that harmonics, the regulation depends on the recoil arch of both barrels in a barrel set rather than harmonics. This arch places the barrel being fired pointing at the same place, when the bullet exits that barrel where the sights were looking at when the trigger was pulled.

On a side by side double the right barrel flips up, and to the right, and the left barrel flips up and to the left.

On an over/under the recoil arches is different than on a S/S. Each barrel flips differently from the other barrel not just opposite from the other but at different rates for each as well. This is because the bottom barrel recoils back, and up and not to either side but simply away from the other barrel. However, the top barrel recoils back, and up but more up than the bottom barrel. This difference is because of the bottom barrel being almost equal to the CG (center of gravity) of the rifle so recoils less up than the top barrel, which is far above the CG of the rifle. This fact makes the O/U far touchier to regulate, and effected far more by a change in weight above these barrels being added.

The weight of the scope, and the quarter rib along with rings has a dampening effect on the whole rifle, and even more so the higher you mount the scope. All this weight retards the recoil arch so much that in most cases, if the rifle is regulated for the scope, especially if it is heavy, destroys the regulation when the scope is removed. This effect is far more likely on an O/U than on a S/S. In either case when the scope is mounted it should be regulated for the irons, and should have the lightest scope rings, and bases one can find, and mounted as low above the bore as is possible, to avoid retardation of the recoil arch as much as is possible. It is far easier to make a workable adjustment of the scope to shoot an acceptable grouping with the scope.

The misconception that double rifle are regulated to cross at a given distance is just that, a MISSCONCEPTION! Properly regulated double barrels are regulated to shoot parallel no matter the range. The misconception comes from the same word being used for filing in the sights for a given range just the same as a single barrel rifle, EXCEPT, that the point of aim for windage on a S/S,, and elevation on an O/U is half way between the centers of each barrel's individual group. In your O/U if the shots are hitting the same hole at any range then it is crossing there as well. Any double rifle that is regulated for both barrels to hit the same hole, then the barrels are crossing at that range.

I would like to ask you who mounted your scope, and re-regulated your rifle?

It is being done by new England gun and I have heard great things about them I was offered a choice either good scope regulation or iron sights when the rifle was first regulated for the new quarter rib with iron sight it shot into a quarter at 100 yards after the gun was sent for re blued it had developed regulation problems and then that where they discovered new problems that they could get the regulation either for the scope or iron sights the iron sight crossed at fifty yards about 3 inches top shooting low and the bottom shooting high with the hornaday factory superformance 165gr and the scope set up shot a 1.25 group at a 100 yards there was no common ground i had a choice so I picked the scoped settings.

I think one concern here is as you stated the scope is 19 oz, Thats pritty heavy. I think if you would have started with a lighter scope there would have been less of a change in regulation.

My O/U double has a light weight scope and it dos'nt care if the scope is on or off. The regulation stays the same.

The scope on my SXS is a little heavier and It dos'nt care ethier but like Mac says the sxs might be a little more tolerant.

If the gun is shooting to regulation with the scope and thats what you want to hunt with then you may allready be where you need to be.

You can if you want work up a load that regulates with your iron sights but thats a little messy in terms of the whole double rifle theory.

You can also try to find a load that works with both but that may not be possible with such a heavy scope.

I wanted to use a red dot scope and all of the in 1.5x6x42 weight in the 19 0z range and since the rifle caliber is 30-06 I wanted to be able to use to at least 200 yards here in KS.

Try the lightest factory load you can find, or load some 130 grainers, try the 220gr factory load (available from Hornaday) and see if your rifle shows less crossing, or none with eithr one, then you are on your way.

In my experience, with SxS's different powders with the same bullets, even at the same velocities, will shoot differently enough to make a significant difference.

Then of course, you can fine tune by changing velocity of the lighter or heavier load.

I don't have experience with O/U's, but if they are anything like SxS's my money is on the hevier bullet to shoot closer to regulation w/o the scope. More bullet weight = more recoil, also, importantly here, I think, more barrel time.

Good luck,

JPK

quote:

Originally posted by JPK:

In my experience, with SxS's different powders with the same bullets, even at the same velocities, will shoot differently enough to make a significant difference.

Then of course, you can fine tune by changing velocity of the lighter or heavier load.

JPK

Agreed.

Different powders can make a difference with the same bullet.

Same rifle slightly different results: Lots of good old posts:

http://forums.accuratereloadin...?r=41010584#41010584

http://forums.accuratereloadin...?r=41910684#41910684



Suggest you try the search function as well.

Mac
Good description of what affects double regulation. I learned from it. Thank You for taking the time to write it.....

Ammoloader, and others I think if I had been doing this install, I would have mounted the new quarter-rib, scope bases and sights, the re-regulated the rifle for the irons with that extra weight. Then mount the scope of choice, and adjust the scope to the center of the composite group with the irons. I would try several different weight scopes till I could match the scopes zero to the center of that composite group of the irons. Addtionally, I think if i were haveing the work done, it would have been done by JJ instead of New England.

However it is not my rifle so none of this means dip!
......................

That a great idea but I would not be happy to compromise the best possible accuracy with the scope, to me iron sights as long as they are on at about 75 yards close to the same plane it should work. The gun will shoot into a quarter at 100 yards with the first pair of shots and the next pair will also shoot in to a same sizes group only a little lower, the original four shot the group after regulation on the target I was e-mailed was 1.25 tall and 1 inch wide. They have the gun almost done but ran out of the Hornaday Ammo I had sent so they need another box to verify the completed job, and of course even calling all the wholesalers that I deal with I was unable to located a box in fact I even called Hornaday and they didn't have any on hand so about two days of calling I found a box and had it next day shipped and went to pick it up and change the label and send it on they (UPS) said I had to send it the slow way the ammunition should arrive by next Monday and hopefully the project will be done next week and I will post the out come, New England Guns has worked very hard on this project and even with the problems they have encountered that still only charged the original bid. RNB

quote:

Originally posted by MacD37:
Ammoloader, and others I think if I had been doing this install, I would have mounted the new quarter-rib, scope bases and sights, the re-regulated the rifle for the irons with that extra weight. Then mount the scope of choice, and adjust the scope to the center of the composite group with the irons. I would try several different weight scopes till I could match the scopes zero to the center of that composite group of the irons. ......................

I'm having a hard time figering why anyone would want to go to the trouble of fitting a scope to their double, and then getting the rifle re-regulated to suit the open sights, and then start trying to find a scope which "might" work, and then sighting the scope to the center of the two "out of regulation" barrel groups.
What you've got there is a rifle which is not scope sighted for either barrel, but somewhere in between both.

A quality scope mounted correctly, gives the shooter far more precision than what the open sights can, by a country mile.
If you fit a scope to a double, and it blows the regulation, re-regulating to suit the scope rather than the open sights is the better option.

quote:

Originally posted by MacD37:
In your O/U if the shots are hitting the same hole at any range then it is crossing there as well. Any double rifle that is regulated for both barrels to hit the same hole, then the barrels are crossing at that range.

That's simply not true.
A double rifle is deemed to be crossing when the individual barrel groups cross over each other on the target.
On a SxS that means the right barrel is printing its group to the left of the left barrels group, and on an O/U it would mean that the lower barrel is printing it's group above the upper barrels group. The two bullet paths have crossed each other.

Just because a shot or shots from each barrel produces a ragged one hole group, does not necessarily mean the groups are crossing.
They could still be apart, and to determine this you merely have to shoot the rifle at longer range.

5seventy believe what you will, I'm not playing your game again!

quote:

Originally posted by MacD37:
5seventy believe what you will, I'm not playing your game again!

Mac,
when it comes to DR's I find your knowledge and indeed wisdom most enlightening.

The wealth of information that you bring to this forum is much appreciated by myself and I am sure many others.

My rifle is regulated to the irons.

With scope mounted, the right bbl shoots higher than the left.

So I sight the scope in for the first bbl shot and that is dead on at 100 yds.

For the second bbl I load a solid such that it comes down to the first bbl. As long as I shoot a solid second and always put the solid in the second bbl this works.

If both bbls are loaded with softs, after the first shot I figure the buff will be running anyway and as poorly as I shoot it will not matter much that the second bbl might be a little high.

Macs thought of experimenting with different scopes is interesting however and I will try that.

quote:

Originally posted by MacD37:
5seventy believe what you will, I'm not playing your game again!

What game would that be then?
I just disagree with your opinion on those topics, nothing more, nothing less.

quote:

Originally posted by rnb:
That a great idea but I would not be happy to compromise the best possible accuracy with the scope, to me iron sights as long as they are on at about 75 yards close to the same plane it should work. The gun will shoot into a quarter at 100 yards with the first pair of shots and the next pair will also shoot in to a same sizes group only a little lower, the original four shot the group after regulation on the target I was e-mailed was 1.25 tall and 1 inch wide. They have the gun almost done but ran out of the Hornaday Ammo I had sent so they need another box to verify the completed job, and of course even calling all the wholesalers that I deal with I was unable to located a box in fact I even called Hornaday and they didn't have any on hand so about two days of calling I found a box and had it next day shipped and went to pick it up and change the label and send it on they (UPS) said I had to send it the slow way the ammunition should arrive by next Monday and hopefully the project will be done next week and I will post the out come, New England Guns has worked very hard on this project and even with the problems they have encountered that still only charged the original bid. RNB

RNB you're on the right track there IMO.
As you said in your original post, you really want to use the scope, and are not concerned about how the irons shoot.
That should turn out to be a great little outfit when you get it back.

Well the gun in question was completed today and will be on its way home on Monday I hope that everything has turned out all right they was to e-mail photos today but have failed to do so but they are very busy because they are moving to a new shop I guess I will find out when I get back from teaching at the State Law Enforcement school Thursday.

Well the wait is over the gun returned today and the targets I was sent are outstanding with the 165 Superformance load in less than one inch and with Remington 220 loads even less about 3/4 of and inch and I am waiting for a breakdown of the shots the target was sent with only the distance and the loads listed not which shot was upper or lower and in what order and I have requested that information. The workmanship is outstanding and after talking to people three months wait is not much of a wait. Will post the targets after I get all the information.

I got the real target on line today and its a far cry from what the gun was doing originally the best it can do now is about 1 1/4 for just a pair not a composite group of at least four shots but the barrel firing order is not listed on the target and it appear with iron sights the lower barrel shoot higher that the top barrel and with scope at 100 years the pair of shots are on a equal plane about 1 1/4 inch apart but that could be the shooter and he just wanted to get the gun done. I want to shoot the gun my self but are unable to find the ammunition that the gun was regulated for from anywhere, when I can shoot the gun and if its not good enough I am sending to jj with hand loads so find the correct ammunition is no longer a problem,