Last summer I found a great deal on a Heym 88B Safari Klassic in 470 and decided to plop down the $9,200.00 (Brand new).
I took it out to shoot it this Fall and it shot 3" low at 35 yards. This was 6 shots with about a 2" horizontal string. 500 gr Woodleigh solids.
I was shooting off a heavy Bogen camera tripod with a makeshift plate and sand bag on top.
The fixed blade on the rear is stamped 35 yards. The first folding leaf is 50 yards.
I thought there had to be something wrong so I took the rifle to Chris here at Heym in Dallas and asked him to install a shorter front blade.
I have the target where they prove regulation from the factory and it shows 2 shots in about a 2.5" spread at 50 yards. Sort of wonder if they faked that target a bit??
Has anyone else experienced this scenario? I was to understand that the rifle was regulated with the Federal ammo I was using.
The groups were good; but 3" low at 35 yards??

EZ

Not everybody "looks" at iron sights in the same way. Even different light conditions can change where the rifle hits for one shooter.

Also on a fairly hard kicking rifle different people hold the rifle different. This alone can have a big effect on the point of impact.

So no, I do not think your situation is out of line.

This is why it is always important to check the zero of your rifle yourself.

Did your sight picture look like this?

http://forums.accuratereloadin...0101804/m/6551079001

Mike,

I put the bead in the V notch as outlined however I put the bead directly on the center of the target, not below as depicted on the picture.

quote:

I have the target where they prove regulation from the factory and it shows 2 shots in about a 2.5" spread at 50 yards. Sort of wonder if they faked that target a bit??
Has anyone else experienced this scenario? I was to understand that the rifle was regulated with the Federal ammo I was using.
The groups were good; but 3" low at 35 yards??

EZ:

Just to clarify, it was shooting low with Federal factory ammo, correct? Did you happen to chronograph it?

The reason I ask is, the performance of the lot you're using may be quite different from the lot that the rifle was regulated with. Most new .470s since the early '90s have been regulated with Federal factory, because that's what has been readily available. That stuff is all over the place though. Federal .470 reference ammo does 2,150 in 24" barrels right at max pressure. A friend in the trade recently velocity and pressure tested some off the rack Federal .470 that did 1,900 fps in his 24" piezo gun, at much lower pressure. A while back, Chris chronographed another lot in a new Heym at 2,240 fps. If the lot you're shooting is substantially milder than the lot your rifle was regulated with, that would easily explain the accuracy and POI issue. I'd try another lot or another brand before making any permanent changes.
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"Serious rifles have two barrels, everything else just burns gunpowder."

Yes Federal! I did not chrono the stuff. It was my first time to shoot it and was just trying it out.
i visited a bit with NECG over the phone and they said if I sent them the barrels that they could mill out the dove tail on the front ramp and modify it to accept their plunger type inserts that would allow easy change outs of beads or the height of beads. Just like on their masterpiece barrel band sights. I thought that might be neat.
The barrels are with Chris now. I could see if he has progressed with the change out. If not I could chrono the box of ammo.
If what you said bares out. It does not do much for my confidence in that ammo. How could you depend on that gun in a pinch for accuracy.
I think it was loaded pretty good. In recoil it made my lighter weight 416 Rem feel like a pop gun.

EZ

Whatever the verdict by Chris, etc, next time you shoot your 470, or any other rifle with a round bead foresight, try holding at 6:00. Its easy to see that you've got the elevation correct when you are placing the round target on top of the round bead. But its difficult to ensure that elevation is correct when you're trying to center the bead in a larger bull and even more difficult if your bead obscures the bull.

JPK

I took the targets over and showed them to Chris.
We kicked some dirt. I understand what you are saying about covering the bull with the pin. With square pistol sights I have always sighted beneath the target as you suggest.
I will chrono that box of ammo and if is "slow" I will just reload or try some of the more "reasonably" priced Hornady when it comes out.
There is no excuse for lousy production QC when you are paying $10.00+ per shell!
Competition is good sometimes!

EZ

EZ,

Slow loads tend to shoot higher not lower. If the load's velocity is anywhere near what its supposed to be, the recoil won't be reduced significantly, but barrel time will be increased a relatively significant amount and the bullets will exit the muzzles further along the arch they describe under recoil.

Also, if the loads are slow, the barrels should shoot apart for the same reason.

Too fast loads tend to shoot low, and will shoot crossing, with the right barrel printing left of the left barrel.

You should do a search here on this double rifles forum under "regulation" and you will find full explanations by me or 400 Nirto Express or a couple of other members.

But keep in mind that most double poi's describe an X as loads are changed from too slow to too fast. The slow loads are represented by the top of the X shooting high and apart. As velocity is increased the rifle shoots lower and the right and left barrels shoot closer.

When the right load is found the rifle shoots a group that looks like a figure 8 lying on its side, with right and left poi's apart only the spread between the barrels at the muzzles. And poi's are this way from muzzle until they hit the dirt. Most rifles (or shooters) can't shoot small enough groups for perfect figure 8's but you are there when the right group is on the right and overlapping the left group.

As the velocity is increased further, beyond the ideal, the poi's will become lower and the the bullets trajectory from right and left barrels will cross. Further increasing velocity makes the barrels cross more and shoot lower. Too fast loads are represtented by the lower portion of the X, with increasing velocity leading to the lower and further crossing poi's.

Personally, I don't much care if a second hand rifle shoot low or high, just so long as I can get it to shoot small individual barrels groups and shoot together. Then I deal with elevation by changing front blade or bead height.

Different for a new rifle, of course!

Good luck,

JPK

I have alott to learn on these doubles. It is my maiden voyage.
I will probably be in contact with many of you adjusting to the characteristics of this gun.
I will also be looking for guidance as to hand loads that will approximate what this rifle should regulate well at.
I have shot various bolts that shot higher with faster loads and sometimes lower.
Fortunately my old Oehler 35 is still kickin' and should be of assistance in this process.
With regard to your comment about faster bullets shooting lower in a double; If that happens to be true in this case and they are @2200+ FPS; I can believe it because my 416 Rem is probably 2 Lbs lighter than this rifle W/O a scope and the 470 is way ahead of that rifle in recoil and I mean significantly.