I've got a pretty new Chapuis that shoots great with the open sights. Pretty much like regulation target included with gun at 50 and 100 (more or less bore distance apart, L barrel about one half to an inch higher). It shoots essentially the same with 5 different brands of rounds and bullets, which is kind of nice as well. So I think the gun is regulated properly. The problem is with my scope on it. I have factory quick release mounts with a Swarovski 1.5 X 4.5 Nova on it.
Regardless of yardage, whether 50 or 100, the spread opens up on line with bull but about 4 inches total spread equally on either side of bull. In other words, my nice little essentially dead on groups with open sights open up to L barrel 2/3 inches to the left, and R barrel 2/3 inches right of the bull depending on the yardage.
Sorry I don't have the capability to show the targets. My last Chapuis 9.3x74R had no such problem. Although many here have reported no change with the addition of a scope, all I can think is the scope is altering things somehow. I am thinking of taking off the heavy Swarovski and putting on a light little Leupold 1.5 x5 . And I surely don't want to move the crosshairs to center one barrel, only to have the other shoot 4 or 5 inches off.
Help!!! My piece of junk Remington SXS -06 is shooting better groups,and it is making me crazy. My eyes are at the point that I really kind of like having a scope on. I don't yet have the ability to reload my own, but I figure since the gun is good without the scope, and with all kinds of different loads, that the scope must be the problem? Right? Any advice from you guys who know would be really appreciated.
thanks
Rick

Let's see if I can get this right from memory without going to Grahme's book...

Doubles are constructed with the barrels slightly crossing, because the rifle will move in recoil some small amount before the bullet clears the barrel (to the right with the right barrel and to the left with the left barrel).

If the barrels are shooting APART, the gun is recoiling FURTHER than it did between ignition and the bullet leaving the end of the barrel, compared to the regulation load.

To bring it together, a FASTER load is indicated, so the bullet will clear the barrel before the rifle moves quite so far.

If it were crossing (not recoiling far enough during the bullet's time in barrel) a SLOWER load would be indicated.

The above, of course, assumes a level of precision in both rifle barrels sufficient to actually measure these differences, and further assumes that all other things are equal, which they seldom are.

Different scopes/scope weights, inconsistent holds, my wife's current mood and the moon phase all seem to influence these challenging pieces of machinery as well. CONSISTENCY is the key.

quote:

Although many here have reported no change with the addition of a scope,

That is the exception rather than the rule with scopes on doubles.

quote:

all I can think is the scope is altering things somehow.

The extra weight of the scope can have an impact on how the barrels move during recoil and - in turn - how the bullets print. Talk to a gunsmith that installs claw mounts on doubles regularly, i.e.: JJ, and they will confirm this for you.

quote:

I am thinking of taking off the heavy Swarovski and putting on a light little Leupold 1.5 x5.

I would say that's worth a try. The Swarovskis are big and heavy compared to the Leupold.

If you have to have the versatility of both, it sounds like you may have to make some comprimises on this particular rifle.

Maybe work up a load that brings them closer together with the scope in place, and plan on them crossing a bit open sighted. At open sighed distances, that wouldn't bother me if i had the scope for longer shots. Just a suggestion.

Just curious. If this was a factory mount, did they give you the option of having the regulation done with the scope on?

Foxhound,

I too am disapointed with my Chapuis 9.3x74 when scoped with a Leupold M8 4X. The normal nice round 6 shot open sight groups become random strikes all over the target with the barrels crossing 3 to 4 inches at 100 yards. I've tried multipe loads to no avail, so it's back to open sights.

Just wondering are you shooting frome a bench? Are you alowing the rifle to touch the bags or are you resting the forarm on your hand so it dosen't touch the bags (no part of the rifle should touch the bags or bench). Have you tryed standing with sticks?
Bill

I have been shooting from a bench with nothing touching the gun but me. I had the opportunity to have it regulated at the factory, but didn't own the scope yet. Since I didn't have a problem with my first Chapuis, I figured it wouldn't be an issue. Wrong.
Question: Since I don't reload yet, would it be reasonable to try a round with a lighter bullet to pick up speed to pull the bullets back in? Or do I just bite the bullet and try another scope?

More often than not, scoping a double requires regulating the bbls. to compensate for the change in mass and barrel time. Bbls. shooting apart indicate too slow velocity or too heavy a bullet (barrel time too long). On the contrary, crossing means too fast/light a bullet (barrel time too short).

Difficult to imagine the installation of optics would alter the shot pattern the way you describe, but it is apparently so. You might consider fixing the gun in a "fixed" apparatus as in V rest snugly held down, padded vice using receiver, not barrels to hold onto, use a magnet base dial indicator to touch the barrels in the area the scope is situated, and as you attach the scope, careful not to move the barrels or contact point of the indicator, note if there is any movement of the dial reading as you install the scope attchment device???? As others with far more knowledge of doubles than I do, the load- dwell time of bullet in barrels- would seem to be the natural answer, but your experience w/ various loads and metalic sights does not lend itself to that concept????
If there was some way you could afix equivalent mass of the scope and mounts to the top of the barrels and still be able to see the sights, and you get the same less desired accuracy results as the scope set up, you could reasonable say the mass of the optics/mounts,etc. alone is the culprit????
Lazer bore sighters would tell you the story if such device could be used while attaching the scope or without the scope??? Just a few suggestions.

I have scoped 2 doubles and 2 double rifle drillings with no regulation problems.

That does not mean it did not shift your regulation.

Recently I was shooting my 450 No2 off bags at the range. I had just recieved the rifle back after a buttstock replacement.

Some people have said that a stock replacement can change regulation also.
The rifle was shooting several inches high, and
I thought that the difference in recoil might be causing the problem.

When fired off hand, the way I developed the loads, the double shot spot on.

Try shooting your rifle off hand at 50 yards ans see if the regulation os still off.

Also on a Chapuis you should shoot the right bbl first.

The bbls on the Chapuis are very thin and the rifle is regulated shooting the right bbl first, which heats up both bbls the ribs etc. and then shootimng the left bbl.

When I shoot my left bbl first at 100 yards the regulation is "off".

[QUOTE]Originally posted by N E 450 No2:
......

Also on a Chapuis you should shoot the right bbl first.

The bbls on the Chapuis are very thin and the rifle is regulated shooting the right bbl first, which heats up both bbls the ribs etc. and then shootimng the left bbl....QUOTE]


Would this be true for a Chapuis that was stocked for a lefty?

That might depend on if they reversed the triggers. Which bbl does the front trigger fire?

On mine, the front trigger fires the right bbl... so I guess you answered my question with a question..... Thanks

I know this is heresy, but my new one has a single trigger. I've had a few with double triggers, and I ordered this one with the single because for whatever reason(length of pull?)I was never as accurate and seem to yank my shots off a bit with the rear trigger. Maybe its all in my head, but this trigger is NICE. And its not for dangerous game, so why not? I don't mean to offend you purists, because I truly prefer my double shotguns with 2 triggers, but the single seems much slicker to me with a rifle. Just an uninformed opinion.By the way, thanks to all for all the information. I think I'll try a lighter scope first; if that doesn't work , its off to JJ.
Rick
*** although no-one has offered an opinion as to my inquiry about trying a lighter/therefore faster bullet first ?

See, it just goes to show you would be better off with a MERKEL DOUBLE RIFLE WITH ADJUSTABLE MUZZLES. Then you could tweak it to your satisfaction. and do it yourself.

foxhound,AzGuy
Just a bump while things are slow and others are debating the 45-70. I was wondering if you ever got your Chapuis rifles to shoot or are you sending them back for re regulation?
Bill

Bill
I tried the lighter scope to no avail. Regardless of the scope, it still shot way off. As soon as I took any scope off, it shot great. I spoke to JJ about the issue; he suspects it is the scope itself causing the regulation problem, and, not to quote him , something to the effect that the smaller the caliber, the more likely the effects from the scope. I sent it to him to re-regulate. And I have my second SPR 22 coming in next week, this one in 45-70, so as to have something to use and play around with in the meantime.
Rick

quote:

I don't mean to offend you purists, because I truly prefer my double shotguns with 2 triggers, but the single seems much slicker to me with a rifle.

You're just ahead of the times with your rifle.

Desightman, all very well thought out advice! The only thing worng with it is,I don't think it will work, wit a double rifle! Stranger things have happened, however!

IMO, it is evident that the rifle was shooting to the sights, and regulating perfectly before mounting the scope, and once the scope is mounted the regulation goes to hell. The regulation went from dead on, to HIGH, AND WIDE, that is caused by the barrels not being able to recoil up, and away from the other barrel fast enough, because of the extra weight, and maybe how high the scope in mounted.

A scope for a double rifle that shoots well with the open sights will always react to a very heavy and/or high mounted scope.

The scope you use should be as light as is posible, and needs to be mounted as low as is posible, to avoid as much adverse torque resistance, to barrel movement as posible.

Knowing something about Swaro scopes,they tend to be heavy, and if you are mounting a very large front belled scope, the rings must be high to avoid the scope touching the top of the rib. With high rings, even the lighter scope may still not help all together. Most of the light scopes like the little aluminum 2-7X32mm scopes, mounted as low as possible, usually work acceptably, and still let you gather a lot of light.

This is an unfortunat turn of affaires! Good luck!
....................

you should have never given up your old chapuis. these new ones are junk and they don't stand behind them.

sorry for you.

you should have never given up your old chapuis. the new ones are junk and they don't stand behind them.

sorry you got sucked in on them.

I wouldn't go so far as to say they are junk, but I've had problems with both of mine. In my case I believe the problems are barrel related, not assembly or fit-up. FWIW - DuaneB

quote:

Originally posted by Will:

quote:

I don't mean to offend you purists, because I truly prefer my double shotguns with 2 triggers, but the single seems much slicker to me with a rifle.

You're just ahead of the times with your rifle.

Will, I knew you couldn't help yourself when single trigger DR's are mentioned.
The lighter 1.5x5 Leupold might fix the problem, it should at least help the issue.

Just a thought and you might ask JJ to check it out if he still has your rifle, but perhaps your rib is slightly loose at the point where the scope attaches and that is changing your barrel harmonics.

Still, I've had the experience of a different, longer and heavier scope (Leupold Vari-X III) attached to a British double with the rings moved, completely messing up the regulation. Put the old scope (Leupold 4X compact) back on and regulation returned to equivalent with just iron sights.

Regards