albert. taylor
New Member
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- Aug 19, 2014
- Messages
- 4
You need to true your vls. Drop it to 3050 fps try that .problem solved
280 AI Ballistics: I need help, I am Confused
- Thread starter rodneymoncrief
- Start date
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dougduey
Well-Known Member
I had a similar problem with a Zeiss V6 scope on my 6.5-284 Norma. I took a long range shooting class, and the problem showed up at 800 yards and beyond. My instructor decided to do a tall target test at 100 yards. and at 20 moa dial up, impact was 21.25". That is a 6% error. For the remainder of the class, my instructor adjusted the BC in his Kestrel to compensate for the error and it worked perfectly. If I didn't get out to longer distances, I would have never known there was an issue with my scope. I also shot a 7 STW with a NF NXS at this shooting class. It was solid and no adjustments were needed
I contacted Zeiss and told them the problem. Aside from the CS person I dealt with being a total a**hat, they had me send it in for evaluation. A few weeks later, I received a brand new scope. This one was dead nuts on for the tall target test.
My ballistics app (Ballistic AE) has an input area for the turret values to compensate for any error.
Plan on sending your scope in or live with it and set up your app to compensate.
I contacted Zeiss and told them the problem. Aside from the CS person I dealt with being a total a**hat, they had me send it in for evaluation. A few weeks later, I received a brand new scope. This one was dead nuts on for the tall target test.
My ballistics app (Ballistic AE) has an input area for the turret values to compensate for any error.
Plan on sending your scope in or live with it and set up your app to compensate.
NBK
Member
Just do a true-up on your ballistic app. Adjust the BC until you are on the money...done deal.
- Joined
- Aug 30, 2006
- Messages
- 286
I agree with most of the previous suggestions. The Oehler chrono is most likely correct. Its never a sure thing with a chronograph. Can you find a Labradar or Magneto speed to check against? That would be step one. Step two, bypass the tall target test and just manipulate the BC. Unless you are trying to shoot WAY out there, this approach will be sufficient. Many variables affect the BC that your individual gun will shoot. For example, I had 2 different 7mms I was shooting a couple of years ago. One had an 8.75 twist and the other an 8.0, the effective BC difference from the same lot of ammo using Hornady 180 gr ELDm bullets was .355 vs .410! This was based on shooting data out to 1600 yards on multiple sessions. Good luck!
With multiple rifles and scopes I've noticed that the error is almost always shooting high at long ranges out to about 900 yards. I have checked calibration on most of them.
I've noticed with many rifles that error tends to be on the shooting high side I think the ballistic data on the Hornady ELD bullets was initially published with a lower coefficient than actual so not to overstate the efficiency until they had good data. A faster twist also increases BC. The Hornady 4DOF is a good app to use. Altitude and temperature and humidity are important to consider too, but none of these factors could account for the higher POI on paper. Scopes were calibrated. Shooting West may account for some of the error, but I wasn't. Another mystery that can be practically accounted for by updating your drop chart.
nikeandros
Well-Known Member
one of ballistic app u can use at the range on the spot is the strelock. ir strelock pro even better.. easy to use and made for solve this problem i had same problem with i cheap Millet lrs.. which i was about to change.. but since i got the app it solve my problem on the field....
another way to fix the issues is to orepare yourself a card the old fashion way and fine tunes your adjustments not taking for good what your ballistic tells you.. but considering on the field what your ammo does.... i'm a cheappo i ways try to save on gadgets apps aetc etc but not on ammo i prefer to shoot more to find what i nead at least is .. real.. and gives me the chance to practice more lol
25WSM
Well-Known Member
I've had 2 vx6 scopes need to be recalibrated. One was close one not so much. The close one we range verified all the clicks needed and did a tape on the turret to get him through his hunt. The rifle was a 7mag and shooting 180 bergers and the dial they sent us shot 6 inches high at 500 yards. All the load info sent was verified by myself to be correct. Definitely do the tall tracking test it will tell you the story. Sometimes bullets just get a better or worse bc depending on the rifle fired in. 208 amax is listed at .650 and in my 300winmag needed corrected to .680 to make it right to 1200 yards.
Shep
Shep
ajkellerusmc
Well-Known Member
What is a tall target test?
EricRF
Well-Known Member
- Joined
- Feb 6, 2018
- Messages
- 65
Basically shoot at 100 yards with a verified zero on a tall piece of paper. Then dial up towards the maximum and shoot again. Then make sure that the higher shot is the same MOA as you dialed.
Starlite
Well-Known Member
Like dok7mm stated. Do a tall target test
good luck
good luck
Santiam338
Well-Known Member
I had a scope that tended to hit high..Speeds and BC were correct.. MIL scope so I made a tall target with the zero at the bottom,another dot at 5 mils up,or 18 inches and another dot at 36 inches,or 10 mil.. After making sure the target was exactly 100 yards and the line running up level,I fired groups at the bullseye,then dialed up 5 mils and fired another group at the zero dot...Repeated at 10 mils,still aiming at the bottom dot..
The 5 mil group cluster one inch above where they were sposed to be while the 10 mil grouped at 38 inches above zero,a full 2 inches high.
I then divided 36 inches by 38,which gave me a correction factor of .947..
.947 is the error in the tracking of my scope.. It is consistent though... I entered the error into my shooter app and after that no more problems...My app and scope were talking the same language..
I don't believe in adjusting speeds and BC's that are wrong trying to make things fit...Better to find the real problem and solve it..
Before I did one more thing I would run this test and see exactly what your scope is doing..
Good Luck.
The 5 mil group cluster one inch above where they were sposed to be while the 10 mil grouped at 38 inches above zero,a full 2 inches high.
I then divided 36 inches by 38,which gave me a correction factor of .947..
.947 is the error in the tracking of my scope.. It is consistent though... I entered the error into my shooter app and after that no more problems...My app and scope were talking the same language..
I don't believe in adjusting speeds and BC's that are wrong trying to make things fit...Better to find the real problem and solve it..
Before I did one more thing I would run this test and see exactly what your scope is doing..
Good Luck.
