I have just come back from trying to zero my Beretta .30-06 and last weekend I was doing the same with a friends Zoli 9,3x74R and found the same issue with both rifles. I only had one brand of factory ammo on each occasion so I suspect it is a matter of findign a load the rifles likes.

Both rifles printed 6-8" apart at 50m and held that out to 100m. The top barrel was shooting high and the lower barrel low.

I have another U/O from Beretta in .375H&H that has never given me these troubles, so I?m wondering if there is a problem here?

The .30-06 barrels are brand new and just came back from the factory special order, and when I tried shootign offhand at 50m, I got a 2" group with horizontal displacement. A friend who was there also tired it and got the same results.

The other groups were shot of a bench rest adn rear bag. Could it be that it doesn't like haveing the forestock resting or that these is contact between it and the barrels?

quote:

The other groups were shot of a bench rest adn rear bag. Could it be that it doesn't like haveing the forestock resting or that these is contact between it and the barrels?

BINGO!

465H&H

ok, thanks for that, now, is there anything I can do other than avoid shooting it off the bench to resolve the problem?
One needs a steady rest for testing ammo...

There's no trouble resting hand and elbows only.

That might be good and fine, but trying to shoot groups at 100meters for load development off your elbows is a it haphazard...
Next time I'll set up a soft front rest with some cusions.

Right. Key is to put up a sandbag for your front rest and then put your double in your off hand and rest that hand on the sandbag. Put the butt into your shoulder pocket and rest your elbow on a bag placed at a comfortable height that keeps you stable and mimics offhand shooting dynamics.

I have also put up a firm cushion at the right height and rested the forend on it, then curled my off hand around into my shoulder pocket to grip the butt (less recoil pounding). The trigger finger elbow is on a sandbag at the right height. Again, key is so the rifle can recoil as it would when you shoot offhand, no part of the rifle is to be in hard, immovable contact with the bench, a sandbag a tree limb or shooting sticks.

Regards

quote:

Originally posted by EXPRESS:
That might be good and fine, but trying to shoot groups at 100meters for load development off your elbows is a it haphazard...
Next time I'll set up a soft front rest with some cusions.

Express, it makes absolutely no difference whether your rifle is an O/U, or S/S, it is still a double rifle, and is effected by the way it is held to shoot! The rifle must absolutely be held, and allowed to recoil as it would when being fired "off hand"! The regulation depends on the recoil arch to shoot properly, and was designed to be shot from an off hand position, with the rifle touching nothing other that the shooter!

Your fore hand MUST hold the rifle, and the rifle it's self must no touch anything other than your hands, face, and shoulder, to shoot properly! The rifle can be rested on sand bags, as long as the rifle doesn't touch them. Place you forehand on the bags, while holding the rifle with that hand. The wrist of the trigger hand can be rested on bags as well,and again as long as the rifle doesn't touch the bag. The worse offender of sand bags is the resting the toe of the butt stock dirrectly on bags, the rifle will never regulate form dirrect contact with sand bags. Addtionally if you have any thoughts about useing a lead sled with a double rifle, forget it! Thos damn things are the devil's own invention, where double rifles are concerned.

NOW! once the resting is corrected, then you can settle the spread of grouping!

The proper resting of the rifle may actually solve all the grouping problems!

If not, however, and the groups for each barrel are in line verticlly (one over the other, on an O/U rifle) then the load is either too slow, or the bullet is too heavy, or both! the BARREL TIME is too long, and the barrels are shooting wide, (bottom barrel shooting on the bottom, and the top barrel shooting on top, but 6-8 inches apart!) Either the bullet weight needs to be lighter, or the load speeded up with the same weight bullet, bringing the barrels closer together.

Initially,the groupings on your target should be shot on two targets, one for each barrel, to determine the best group for each barrel. fired from cool barrels, for the first shot, and with the 3 shots from each barrel fred RT,LFT,RT,LFT, RT, LFT If the load you are useing shoots acceptably in one barrel but not in the other, then the load is not going to shoot better than the most open barrel's group.

For the two targets, place the aiming dot, in the exact center of an eight and one half X eleven inch piece of printer paper. When you shoot a 3 shot group from each barrel on it's on target, with the front sight exactly on the center aiming point, of each target. Now take each target, and find the "CENTER" of each group, on it's own target, Now, lay one target over the other, lined up exactly, and with a ball point draw through the holes on the top page, onto the bottom page, and poke a pin through the target on top, at the center of that target's group. This will give you the center of each barrel's group, and where that center is in relation to the aiming point on the combined target. If they are still too wide, then spped it up a little more till the center of each barrels group is on it's own side of the aiming point, by about half the distance between the certers of the bore of eact barrel. Whe this is reached preserve the load data, and stop, because the rifle is asregulated as it will ever be! I useing va scope the scope shopuld be adjusted to aim at a point half way between the centers of each barrel's group, not on the center of either group.

The top barrel's center of it's group should be slightly above the center of the target, and the bottom barrel's group center should be slightly below the aiming point, for an O/U rifle. The rifle's two groups should be slightly oval in shape, with the center of each barrel's group on it's own side of the aiming point. If that happens the load is as good as it will get!

This advice is free, and is available to use if needed, or not, your choice!

Thanks Mac, that's some good info. I am well aware of the dnamics of recoil and the differences that hold and rests can make to POI but I have not encountered a rifle that gave such wildy different results when changing the firing setup. I usually use a bipod for most of my range work, then if I'm not planning on using the bipod for hunting I just take it off and re-check zero off a backpack, or bags. Usually it is pretty close or spot on in my bolt hunting rifles.

I am going to Burkina Faso tomorrow to hunt with one of these doubles and I'll make sure to zero if off bags and hands.
I'll post a report when I get back.
Cheers.