doublegunshop.com - home Forums General Discussion Double Rifles, Paradox Guns & Gauge Rifles @ doublegunshop.com UPDATE Double rifle zeroing question

Let me preface this by saying that my accuracy expectations are based on my experiences with my Chapuis 9.3x74R. That rifle spoiled me; it put 2 pair into 1 /12� at 100 yards all day long. So, that is my gold standard to judge by. Maybe that is wrong but it�s my baseline to compare against.
Which way to zero a double rifle with what I call only fair accuracy. The factory standard for the company that built this rifle is 10 CM at 100 M so its within factory specs. I have been shooting double rifles for 15 years now and am not an expert but no beginner either. There is always more than one way to look at a problem and I am asking for opinions and insight to possible similar situations and solutions you may have come up with.
I am using Norma 150 Gr. Factory loaded 7x57R ammunition. I have also tried Privi 139 and get similar results. Scope factory mounted and regulated (Leupold 2x7 VX-R scope) in EAW mounts.
Shooting with rifle on my hands, my hands supported with a sandbag in front and up against my shoulder at rear. Fore end is gripped by my hand.
My 7x57R double rifle shoots 2 pair into about 3 1/2-4 inches at 100 yards. Each barrel puts its two shots to its respective side of the bull. Right barrel to right side etc. each barrel puts two shots within an inch of each other.
So, here is my question.
I could zero with a center hold and both barrels will hit 1 ��- 2� to either side of center and just accept 4 MOA group average. Or I could zero with the right barrel shooting point of aim/point of impact and left barrel would be 3 ��-4� to left of that. With this zero I have first shot where I could be precise as hell and second shot most likely game would be moving then.
At 50 yards or less, either zero would be good enough regardless, it is only when getting out to 100 or more where it becomes more critical for good hits. And it is the longer distance that you need the least amount of error.
I am using this primarily for whitetails. At maximum this is a 200 yard rifle. Most of my shots are 50-100 yards but I do have a few meadows I can easily reach out to 200 from a stand. So, what would you do. There are pros and cons to each method.

What are your thoughts.

UPDATE: shot rifle today with Norma 150 Gr and Privi 139 gr.
the Norma still shoots terrible. The Privi however shoots a whole lot better Good enough tat I am zeroing both barrels and the phot shows a group of 3 rights and 3 lefts at 100 yards. center of target as aiming point. I then shot it at 200 yard with that zero and it was about 6" low and about 6in. group but well centered. we are good to go until I can start developing a load for it.

Have you read Wright's book? Do you handload? From memory, the general rule of thumb is that if the barrels shoot apart, the bullets are too slow...

Brian,
I can't see any problem with the way you are shooting the rifle and cadet is correct about the "school solution" to a rifle "shooting wide". However, to get higher velocities you would have to go to a bullet that is lighter than you want or handload the bullet you do want. You said the scope was factory mounted in EAW mounts, but didn't report the make. Most doubles are regulated without scope and if the customer wants one, it is mounted later, usually outside the factory. I know from sad experience, mounting a scope on an already regulated double can change the "regulation". Did you buy the rifle new? If so, did it come with documents describing the ammo it was regulated with, maybe with a sample target? If you have that info and the ammo is different than you tried, you may want to check it. You could have the rifle re-regulated, but that would be an expensive and time consuming operation. You might want to try RWS ammo, it may give higher velocities than the Norma, and I'm sure it will be faster than Privi(both are good ammo). New England Custom Guns is now importing RWS ammo.
Mike

Gentlemen,
Thanks for the responses but they still don�t answer my question.
I know about loading and velocity and its impact on dispersion. I have tried 4 different loads in the rifle.
It is factory regulated for Norma 150 gr.
I sent Chapuis a new in box Leupold 2x7 VXR to regulate at the factory. It was regulated with the scope and Norma 150 gr. That�s why I sent it to factory, I didn�t want the headaches of re regulating.
I am not interested at handloading at this point in time, no time to do it. I am asking for opinions on which type of zero makes the most sense with the grouping I have with the ammo I am using.

Brian, have you actually used this rifle on deer? The reason I ask is that I have found that even a relatively mild cartridge, like the 8X64S, is excessive for the 150 to 200 pound white tail deer we have here in West Tennessee. I, too, have a 9.3X74R double rifle, but I would no more think of using it for deer than I would my .350 Griffin & Howe Magnum or my .350 Rigby Magnum. I bought mine with the idea of using it on driven wild boar, but at my age and given my health problems, that dream is rapidly fading. Still, I feel no temptation to use the rifle on deer. My .250-3000 Savage will do the job with ease and far less meat damage.

It sounds to me as if Brian wishes to use his 7 x 57 double rifle for deer, and not the more accurate 9.3 x 74R. And I think his question is our opinion of how he should sight in with a double rifle that is capable of about 4" 100 yd. groups. Considering that the left and right barrels group left and right of point of aim respectively, I think I would continue to use the same center hold and rely on a little Kentucky windage for those occasional long shots from a stand which are likely to be taken at stationary deer anyway. To me, sighting for more precision with the right barrel doesn't make a lot of sense if it means that the left barrel will be up to 4" off with a 100 yd. shot. 4" of built-in lead might be a good thing if a wounded deer runs in the right direction, but it would be a liability if it runs in the wrong direction. It might also be prudent to consider that this is not the ideal 200 yd. rifle, and to go with something more accurate when those across the field shots are more likely. This particular gun is still quite useful as is for still hunting in the thick stuff and stand hunting where under 100 yd. shots are more typical. Of course, when time permits, more extensive shooting to re-regulate with different loads might make this 7 x 57 more suitable for long shots.

Were I in your situation I believe I would set the scope where the cross hairs are centered between the tow groups, accept the 4" grouping you mentioned. Reason being you will always know the right and left barrels are going to shoot to their respective side. I believe for me it would be easier to remember to hold 2 inches left for the right barrel, or vice/versa, if I found need for a bit more precision...but that's just me.

Now, if the rifle were mine I'd be working up a proper load.

We all have different opinions. Since you don't want to handload, I vote to sight the right barrel 1 1/2 inches high and centered windage wise. You will seldom need a second shot, but will always need the first. It is more important to have the first shot where you want it than a second.
Mike

Thanks for the additional insight.
This all deals with the 7x57R for white tails. not the 9.3. That was just for info purposes

just what I was looking for. Not that I don't want to reload, just don't have the time. Need to be able to grab a box of ammo and go hunt.

I think I will go with the 1.5" high with right barrel (front trigger) centered and call it good.
as a side note, have any of you used the privy 139 gr load on white tails? I am curious as to how the bullets performed. I have heard mixed reviews on them.
Hopefully soon (next year) I will have more time and will be able to hand load and get it to shoot the way I think it is capable if. Just want to take it out and use it this year.

You're probably okay at shorter distances, but it might not be a bad idea to try it a 150 or 200 yds to see if the groups continue to spread predictably, they may not. In the end, the season is here, and it might be good to be confident in the first barrel.

I don't know about the privy ammo, but if there's a chance that you reload down the road, see if you can save the brass from the same make and maybe same lot number. Only thoughts, good luck with it.