I have a Sabatti Classic in 9.3x74 RWS .
Accuracy at 50 mts with Hornady 286 gs ctgs and reloads is less than 1 inch spread firing with both barrels .
I had decided to install a scope sight , and install a Hertel & Reus scope , with Sabatti mounts , that are reliable and very well constructed
After this "improvement"my groups are 5 inches spread horizontally at 50 mts.
If I take out the scope groups return to ess than 1 inch again.
Have anyone know what is happening?\
Can the instalation of the scope , do that barrels vibrate differently to ruin the accuracy?

Thank for your help

How is each barrel's accuracy with the scope, shooting 'right only' and 'left only' for groups, not right-left..?



Cheers
Tinker

Raul, I think the short answer is that by mounting the scope you have affected the regulation of the rifle. Now, I have not had this happen myself with my K gun, but others, and other guns, have. If you reload you can develop load that will group better with the scope. What ranges were you planning on using your 9/3x74R? One inch at 50 meters is pretty good. Have you tried open sights at 100 meters?
Peter.

How big is this scope? Possibly by using a small scope like a 1.5X5 Leupy..... Tall mounts and big bells on the scope aren't good IMO.

quote:

have a Sabatti Classic in 9.3x74 RWS .
Accuracy at 50 mts with Hornady 286 gs ctgs and reloads is less than 1 inch spread firing with both barrels .
I had decided to install a scope sight , and install a Hertel & Reus scope , with Sabatti mounts , that are reliable and very well constructed

Hi Rauel:
Any good thing can come out of Sabatti

1" that is almost if not perfect accuracy for a double that has its barrels apart an 1"
center to center.

"Mounts that are reliable and very well constructed" mean to tell me they can build something that is reliable, strong and accurate.

Since your rifle is not crossing, you can play with the load a little bit without any fear of loss of velocity. You will be surprised some times what a little change in velocity can do to the regulation of a double. At least that is what I hear.

Good hunting/shooting and God's best.

Malek

Raul, I'd look at the easiest problems first.

1) check every mounting screw and make certain that all are properly tightened.

2) If the mount is a quick release type check to see if there is any looseness. I had a similar problem once and the issue was an adjustment screw that had become loose. I found it by clamping the barrels in a bench vise with the scope mounted. (with wood blocks to protect the finish). With the barrels held rigidly I could actually feel the movement when I tried to move the scope.

3) If #1 or #2 don't correct the problem try a different scope.

I have also heard that a heavy scope can cause problems.

Thank all for your replies.
I´d checked mounts and scope, and change scope also .Problem is the same.
I´ll try to develope a reload to try get some respectable accuracy .
tinkerer - accuracy fromach barrel at 100 yds with scope mounted is 2 inches each , but 6 inches apart.
Peter - accuracy with open sights at 100 yds is 2 -3 inches

quote:

Peter - accuracy with open sights at 100 yds is 2 -3 inches

Raul, what more would you expect from a scope? What game at what ranges would you be hunting?
Peter.

Peter

Obviously that 2-3 inches in a DR with open sights is more than one can expect. I allways thought that DR are for use with iron sights , to hunt beyond 100 mts and big animkals.
If I want a sub mos rifle I would go with a bolt rifle etc.
But one day I wake up thinking in installing a scope to that DR and then begun the problem.
My asking is only to clear me what is the reason of accuracy loosing after the instalation

No disagreement here Raul! I have several doubles, all scoped. Nothing wrong with getting the most out of them.
Peter.

quote:

Originally posted by Raul Urrestarazu:
I have a Sabatti Classic in 9.3x74 RWS .
Accuracy at 50 mts with Hornady 286 gs ctgs and reloads is less than 1 inch spread firing with both barrels .
I had decided to install a scope sight , and install a Hertel & Reus scope , with Sabatti mounts , that are reliable and very well constructed
After this "improvement"my groups are 5 inches spread horizontally at 50 mts.
If I take out the scope groups return to ess than 1 inch again.
Have anyone know what is happening?\
Can the instalation of the scope , do that barrels vibrate differently to ruin the accuracy?

Thank for your help

quote:

Originally posted by Raul Urrestarazu:
But one day I wake up thinking in installing a scope to that DR and then begun the problem.
My asking is only to clear me what is the reason of accuracy loosing after the instalation

Raul, the addition of a scope sight on a double rifle is most time problematic to regulation if not done properly.

The scope to be placed on a double rifle must first be as light as it can be, and secondly has to be mounted in equally light mounts and rings, so the over all weight of the sighting system is as light, and low as is possible.

The reasons for this are as follows:

#1 the side-by-side double rifle depends on the amount and direction of the recoil “FLIP” to regulate properly. “FLIP” is a word used, in this case, to mean when the RIGHT barrel is fired, the rifle recoils BACK, UP, and to the RIGHT away from the other barrel, and vice versa for the LEFT BARREL.

#2 The heavier the scope and rings and bases are the more it will effect this “FLIP” of each barrel, thus effecting the regulation of the rifle. The higher the scope is mounted the more torque involved negates the proper movement of the barrels while the bullet is traveling down the bore before exiting the muzzle.

The fix is to find as light scope as you can, and mount it as low as you can to lesson the amount of torque’s retardation of the muzzle FLIP.

The reason for all this is, can be seen by taking the barrels off the rifle, and clamping the under lumps in a padded vice, with the iron sights lined up on a target at the distance the sights are cut for. NOW, take two empty cartridge cases with out primers, chambered in the rifle’s barrels. Use these to look through the flash holes of each barrel like looking through a PEEP SIGHT at the target. What you will see is the RIGHT barrel will be pointing at a place on the target that LOW, and LEFT of the point of aim, and the other barrel the exact opposite, the lines of sight through the barrels crossing, and low, with the barrel at rest.

This is so that when the sights are on the target the RIGHT trigger is PULLED, the rifle begins it’s recoil “FLIP” to the right, and back, and up so that when the bullet exits the muzzle, the barrel is pointing at the same place where the sights were pointing when that trigger was pulled. This is a phenomenon that is called BARREL TIME, and with a proper load and no changes in FLIP the rifle will shoot parallel never to cross down range. The exact amount and direction of the FLIP of the barrels is critical to make the rifle regulate. Any scope may destroy regulation, on some doubles, but one that is too heavy, or mounted too high, or both or either may also destroy regulation. However the lighter the scope weighs, and the lower the scope can be mounted is far less likely to totally destroy the regulation.

I would try to find aluminum bodied scope with a straight tube with no objective bell, and some very low rings, also aluminum, and mount that before I started changing loads. Loads will not change the torque brought on by weight and height of the scope. We know this is the problem because the rifle regulates properly before mounting the scope. If the scope you can find is as light, and mounted as low as is possible, and the regulation is still badly effected, then you might try one of the little Doctor red dot sights which only weigh a few ounces. Many of the DRSS members have gone to these little sights on their double rifles, with very good success.

…………………………………Good luck Raul!

Mac37
Really thanks for your raply . It is the most inteligent answer , and clear me enogh

Thank you again

raul

You have added too much weight and affected the barrel recoil dynamics as explained above. Those Hertl and Reus scopes are hogs; get a light straight tube scope like a leupold 1-4 or 1.5-5 and that will help. And the 9.3 DRs are lighter than Nitro ones so are more sensitive. I have scoped 3 so far and in all cases the accuracy was not affected, but I used light scopes on heavy rifles. On my Sabatti 450 I put a Leupold 1-4 Shotgun scope; works great. OR, even better; put a holographic sight on it; they weigh nothing. A friend has one on a 45-70 and is fast death on running hogs.

Some people have reported a change in zero/regulation after scoping a double.
However I have scoped a Chapuis 9,3x74R and a British 450/400 double and did not have any Drama.

Also if you are trying to shoot your scoped double off of bags like a bolt rifle then that is probably your problem...