Rifle shooting high consistently with drop chart

[ShtrRdy]

There's lots of suggestions here, but you should make sure the scope adjustments are moving the distance you think they are. Bryan Litz put together a nice video describing the Tall Target test.
https://www.youtube.com/watch?v=12Wf0Cuwwi8

 

[WapitiBob]

You don't need a chrono.
You need accurate scope height, close on elevation and temp, use the bc listed making sure it's g1 or g7, and a muzzle velocity from your reload book or off the box of ammo.
Zero the turret at 200 yard zero then sight in at 500. Adjust the velocity in the calc so it matches your 200 zero and the 500 mark then shoot in 800. Adjust again. 200 and 800 will be on and if 500 is off you can mess with the bc and or scope height -slightly to see what it does for you. At this point it isn't perfect but close enough to get trigger time while you learn and finish dialing in your calculator data.

As noted above if it's a cheap scope the clicks may be off, which you can account for in the calculator.

 

[FEENIX]

I'm reading Bryan Litz's book.
To measure the scope height he recommends:
Measure the diameter of the barrel then divide by two.
Measure the diameter of the scope then divide by two.
Measure the gap between them.
Total the three measurements.

He recommends you use calipers.

I don't know much, but I hope I can help you with his instructions.

Ed

Ed,

It's basically the same as ...

Pull the bolt out halfway and measure C/L of bolt and C/L of scope.

You also go to YouTube "How to measure scope height the easy way" by Sam Millard.

[ame]https://youtu.be/fFrNrhqcEiQ?t=9[/ame]

Ed

 

[Greyfox]

A few questions for the OP:
How does the rifle group at 200 yards?
What velocity are are using in your BC?
What are the elevation settings in MOA you are using at 500 and 700 yards that produced the high POI?

 

[Kelpy]

The best I can answer thos questions.

200 yards is approx 1 - 1.25" 3 shot groups. If I shoot 5 shot groups it opens up a hair but still sub MOA.

I am just using the BC on the box. I don't know what velocities they calculate it at??? My velocity through the chrony was 2582fps (seems slow) with 63.5gr of IMR 4350. I could develop a faster load next year with a faster powder.

500: 8.73 MOA
700: 15.81 MOA

If I get off work early enough tonight I am going to shoot a big sheet of paper to know exactly how high of impacts I am getting.

Thanks for the input so far fellas! Kelpy

 

[Canadian Bushman]

The best I can answer thos questions.

200 yards is approx 1 - 1.25" 3 shot groups. If I shoot 5 shot groups it opens up a hair but still sub MOA.

I am just using the BC on the box. I don't know what velocities they calculate it at??? My velocity through the chrony was 2582fps (seems slow) with 63.5gr of IMR 4350. I could develop a faster load next year with a faster powder.

500: 8.73 MOA
700: 15.81 MOA

If I get off work early enough tonight I am going to shoot a big sheet of paper to know exactly how high of impacts I am getting.

Thanks for the input so far fellas! Kelpy

More than likely velocity is much faster than 2582. I would change this number until your drops correspond and see where that puts you when you shoot further.

 

[Greyfox]

The best I can answer thos questions.

200 yards is approx 1 - 1.25" 3 shot groups. If I shoot 5 shot groups it opens up a hair but still sub MOA.

I am just using the BC on the box. I don't know what velocities they calculate it at??? My velocity through the chrony was 2582fps (seems slow) with 63.5gr of IMR 4350. I could develop a faster load next year with a faster powder.

500: 8.73 MOA
700: 15.81 MOA

If I get off work early enough tonight I am going to shoot a big sheet of paper to know exactly how high of impacts I am getting.

Thanks for the input so far fellas! Kelpy

Your BC program is pretty much the same as what I get in Shooter when I input your data. The BC on the box of the 215 is generally very accurate. Given there isn't something else going on with your rifle or scope, your high POI drop data would indicate that your 2582FPS is low and the actual velocity should be in the 2800-2900FPS range. I shoot 215's in my 300 using 77.7gr of Retumbo to get 2865FPS.

MY corrections are: 500 yards-6.8MOA
700 yards-12.4MOA

 

[Kelpy]

Ok, so i'm trying to run the numbers from this mornings shooting. I have gotten myself a little confused so maybe someone smarter can help me with the math. . .

I am zero at 200yds

BC .696

Velocity 2782

Elevation 5800

Temp 44deg

Scope Height 2.18"

Shot 2" high at 645 yards with 11.75MOA dialed into the scope

Shot 12" low at 871 yards with 19.25 MOA dialed


Thanks for any and all help! Kelpy

 

[smokeumm]

Very well could be a variance in velocity. Could be caused by neck tension or load. Easiest way to solve those two issues is to turn the necks on your brass or by shooting a ladder test at 400 yards during load development. I would start with preforming a ladder test.

 

[AZShooter]

I have only encountered three rifles to date that didn't perform as suggested by the input data to the ballistics program.

When it happened the first time I checked and rechecked the inputs. Drove me nuts.

I tried to manipulate the comeups by lowering or raising the BC. It would work for one distance but to get it to match several impact distances couldn't do it.

I began to conclude that the only input that worked was changing the velocity.

Recently a 338 RUM shooting the 300 gr matchking shot low at all distances. At first I thought the POI at 100 had changed, it didn't. Eventually had to lower the velocity from 2850 to 2800 and it was good.
You wouldn't think a CED and a magnetospeed would be that far off when both showed same velocities. What is causing this? Bullet not perfectly stabilized?

I have thought about this often. Perhaps some other factors are at work. Input POI at 100 yd or 200 yds was wrong? Shooting uphill/downhill? Headwind, tailwind? Shooter's form is off? Not enough rounds fired for a good sample?

I just sent Bryan Litz an e-mail on this thread. Hoping he has the time to respond.

 

[wasgas]

Do you have a 20moa rail or ring setup?

 

[AZShooter]

Wasgas,

One that underperformed has a 20 MOA picatinny rail. The other two didn't have rails.

I added that extra height as part of the inputs under scope height. Is there some other reason for mentioning it?

 

[wasgas]

If you are using an moa rail the offset your scope is no longer level with the bore and will have some affect on drop chart apps

 

[Barrelnut]

If you are using an moa rail the offset your scope is no longer level with the bore and will have some affect on drop chart apps

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