Ballistics question

Rzrbck918

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Have a friend who has a 300 win mag and says he is 3.7" high at 100 yards instead of the roughly 2" high he desires to be. Aside from resighting in which he should do, he asked if because it is roughly 1.7" higher than it should be if that 1.7" in transferrable to the ballistic chart at say 300 or 500 yards. I hadn't ever thought of that question and I wasn't sure if it was that simple or if the math was based on minutes of angles and arcs that were not simply additive and he would see a greater change in POI at greater range.
 

Dougfirtree

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Are you asking if the bullet will hit 1.7 inches higher than the ballistics chart says at 300 yards, because it's 1.7 inches higher at 100 yards? If so, the answer is no. As suggested above, a good ballistic calculator should give you a decent estimate of what it will actually do and then actual range time should tell you exactly what it will do.
 

BucksnDucks

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Have a friend who has a 300 win mag and says he is 3.7" high at 100 yards instead of the roughly 2" high he desires to be. Aside from resighting in which he should do, he asked if because it is roughly 1.7" higher than it should be if that 1.7" in transferrable to the ballistic chart at say 300 or 500 yards. I hadn't ever thought of that question and I wasn't sure if it was that simple or if the math was based on minutes of angles and arcs that were not simply additive and he would see a greater change in POI at greater range.
If he's not going to the range the math is simple if he knows velocity and what projectile (BC and weight) he's shooting. There are other variables involved but the "simple" answer of zero and various yardage POI is easy to determine.
 

Rzrbck918

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Are you asking if the bullet will hit 1.7 inches higher than the ballistics chart says at 300 yards, because it's 1.7 inches higher at 100 yards? If so, the answer is no. As suggested above, a good ballistic calculator should give you a decent estimate of what it will actually do and then actual range time should tell you exactly what it will do.
That is what I was asking, thanks!
 

winmag

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1.7” at 100 yards = 1.7 MOA.

So if he is 1.7” higher than he wants to be at 100 yards, that is also 1.7 MOA higher than he wants to be. This is transferable to all ranges on his drop chart; he will hit 1.7 MOA higher at all ranges.

If he has a quality scope that adjusts accurately, why not just adjust it down 1.7moa so he’s the 2” high at 100 yards that he wants?

As others mentioned, if he doesn’t know this then he shouldn’t be shooting beyond point blank range for his rifle. In other words, not shooting at distances that require adjustment or holdover.
 
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std7mag

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1.7” at 100 yards = 1.7 MOA.

So if he is 1.7” higher than he wants to be at 100 yards, that is also 1.7 MOA higher than he wants to be. This is transferable to all ranges on his drop chart; he will hit 1.7 MOA higher at all ranges.

If he has a quality scope that adjusts accurately, why not just adjust it down 1.7moa so he’s the 2” high at 100 yards that he wants?

As others mentioned, if he doesn’t know this then he shouldn’t be shooting beyond point blank range for his rifle. In other words, not shooting at distances that require adjustment or holdover.
1.7 inches at 100 yards, isn't 1.7 MOA.
Close, but not exact.
 

rjthehunter

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If you dial, don't sight in 2" high at 100 yards. Sight in dead on at 100 yards. If he doesn't dial, then tell him to sight his scope in at 100 yards and move up 2moa.

How are you calculating velocity? Is he reading what the box says for velocity, or are you shooting over a chrono to verify? The question is confusing. But if he's 3.7 inches high at 100, and he wants to be 2. He should adjust down 1.62moa as stated above, and the rifle should be 2 inches high.
 

Don Fischer

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My chronograph gives me trajectory figures. I never trust them and go out and shoot against them at the real range. Darn thing has never been much wrong! But I still think it's a good idea to shoot against the data.
 

Rzrbck918

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If you dial, don't sight in 2" high at 100 yards. Sight in dead on at 100 yards. If he doesn't dial, then tell him to sight his scope in at 100 yards and move up 2moa.

How are you calculating velocity? Is he reading what the box says for velocity, or are you shooting over a chrono to verify? The question is confusing. But if he's 3.7 inches high at 100, and he wants to be 2. He should adjust down 1.62moa as stated above, and the rifle should be 2 inches high.
Im sure he's reading the box. He's been a lifelong bowhunter and this is his first new rifle. Just getting going in the shooting side of things and has asked some questions I've simply never thought of.
 

Don Fischer

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I've fooled with long range just a bit. Had my 6.5x06 sighted in at Max Point Blank Range and ran it through my Ballistics calculater and worked just fine. In the end I had my 6.5x06 dialed in for MPBR but if I wanted to could dial in longer ranges. Shooting those longer ranges showed it works!
 

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