puzzling results...please help

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willyqbc

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Ok here the situation, I am shooting my new Remington model 700 LSS in 30.06. Shooting 165grn interbonds over 59 grains of H4350 (no pressure issues), my chrony has them at 2930fps +/-6fps. Now heres my issue, over multiple trips to the range I am getting under 1" groups at 110yds 2 3/4" high....now move out to 330yds and my groups ar around 2 1/2-3" but are only 1.5" low at 440 the group is around 5" and 9" low, approx 24" low at 540yds. These numbers all match up on a ballistics program to that bullet going 3500fps.....thats just not possible. So given that the results on paper seem pretty consistant over multiple trips to the range can anyone come up with an explanation. I am going back tommorrow and will shoot 220yds and see if the results fall in line with what I am getting at all other distances.

Thanks
Chris
 
Are you shooting from one position or moving back at those large ranges that have differant firing lines. You may be just looking at the target with higher or lower head position , scope setup ,parallax , all could mess you up.
I would shoot it again at those ranges and see what results you get...
Frank
 
our range is in metres (thus the 110yds, 220yds etc) it is 540 yards long....flat out to 440, 20degrees up to the 540 which i know will shoot shorter than 540. i shoot all ranges from the same rest on the same bench. I have shot these same number the last 3 trips to the range with the exception of 220yds. Going out again tommorrow to shoot 110, 220 and 330, maybe the 220 yd results will tell us something useful

Chris
 
Suggest your double check the data you are plugging in to the ballistics program. Elevation, temperature, velocity and ballistic coefficient can all have a large effect on the calculated trajectory. Also check to make sure the sight height is correct.

Other than that, go with what you see on paper, not what the computer says.
 
As Suputin says , the paper does tell the truth. A variable that many overlook is how high center of scope is to center of bore.

Todbartell
Having you optics mounted high off the bore does NOT change the actual bullet path, but it does change where the bullet intersects the line of sight both times, which can give the illusion of a different trajectory.
 
if your results are repeatable then I will suggest these possible solutions:

The scope is very high and causing you to aim higher then a lower scope position. Unless you have that scope a couple of inches off the action, this will not be the case.

That the data you are inputing is wrong. What drag curve (G function) are you using? If you use G1, you are completely wrong. Try a G5 or G7. That might bring your data more inline.

The interbonds are the longest 165gr 30cal bullet I am aware of. I have been shooting Hornady poly tipped bullets in a variety of cals and do find some that fly way better then their numbers would predict.

Wouldn't surprise me that this bullet follows a G7 drag curve. This means that this bullet flies with a much lower coefficient of drag. There is two components to the bullets drag numbers. BC and G curve. Don't ask me the math as I don't know.

Just play around with the program and change the G functions. Makes a huge difference in LR ballistics.

Most HP match bullets are a G5. Some of the Amax and SST's follow a G7 curve (at least with my adjustments and data). G7 is usually only found on very specialized VLD bullets. A significant improvement.

Just make sure your data is repeatable and groups small enough to draw reliable conclusions.

Jerry
 
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well from this and other forums and some help from Todbartell of all people I think we have narrowed the problem down to probably being due to high rings....measured 2" from center of bore to center of tube. I have a new luepold and LOW dual dovetails on the way. hopefully clears it all up. Thanks for the input folks!

Chris
 
well my results today confirm what was suspected i think. Still 2 3/4" high at 110yds, and 1.5" low at 330yds. but checking 220yrds I find that I am 4 1/2" high. It has been pointed out that high rings will make you point uphill to get the bullet and crosshairs to intersect at 100 yards....my bullet is still climbing....not sure where it tops out, and while its great for long range shooting, its no good for practical hunting ranges. Thankfully the Luepold and LOW rings should be arriving in the next week or so.

Thanks again guys
Chris
 
Chris, why not just adjust your POI to dead on or a bit low at 220yds. I bet it will be dead on at 100yds and still within the ribs at 300yds.

I have found that a high 100yd zero has gotten me in trouble more often then it has helped. I now sight my rifles to be dead on or just slightly high at 100yds. This puts me a bit low at 200yds and 10 to 14" low at 300yds.

Since most of my deer are shot around 100yds when I am still hunting, I never have to worry about aiming high or low when a quick shot is needed. If the game is further away, I have the time to adjust or at worse, hold on the spine and let the bullet drop into the boiler room.

At further distances, if I don't have the time to use my rangefinder and adjust, odds are a hasty shot would lead to a wounded animal anyways. My ability to tell distance sucks.

If the elevated scope gives you a more comfortable hold, I would leave it. Putting a scope too low can increase felt recoil and hurt you ability to shoot accurately from field positions.

I want the rifle to fit me, not the other way around.

Jerry
 
the high rings were just to accomodate a 50mm scope that used to be on the rifle. I have a target turret coming from Stoney Point so that should take care of long range work. For zero I will play a bit and find the best compromise to keep me +/- 3" as far out as i can get.

Thanks again guys
Chris
 
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