Using Angle Cosine Indicators

[silentnoise]

After reading various articles and posts regarding the use of Angle Cosine Indicators it seems that the line of sight distance to a target divided by the angle cosine does not provide the true distance to be use in determining the correct value for a center of aim hit. If this is correct, why are Angle Cosine Indicators so widely used for long range and steep angle shooting? Even the Angle Cosine Tables would be off if they are not taking into account the time in flight effects of gravity upon a particular projectile. I am interested in determining whether or not there exists a mechanical device which would accurately reflect the correct solution to this dilemma. I try not to rely on electronic devices while in the field hunting as weather conditions often hinder their use. Ballistic calculators are a help, but can only take you so far. I am not trying to invent the wheel if someone already has a patent on it.

 

[ShtrRdy]

The Angle-Cosine indicator is used to estimate a drop correction for a angled shot. It's not exact but it gets you close. The techniques used are the "Rifleman's Rule" and the "Improved Rifleman's Rule". I've run a couple examples for myself and the Improved Rifleman's Rule gets you closer to the correct answer. I guess that's why they call it Improved.

The best approach is a Ballistic Calculator. Entering the correct information will give you a exterior ballistics solution that's as close as you can get. These use Time of Flight and the component of gravity to determine drop on an angled shot. But you said you don't want to count on an electronic device so that's not going to work for you.

So I think your next best bet would be one of the mechanical slide rules such as the Accuracy First Whiz Wheel. This attempts to put the Ballistic Calculator into a mechanical calculator.

https://www.accuracy1stdg.com/store/itemDetail.cfm?prodID=504

 

[silentnoise]

The Angle-Cosine indicator is used to estimate a drop correction for a angled shot. It's not exact but it gets you close. The techniques used are the "Rifleman's Rule" and the "Improved Rifleman's Rule". I've run a couple examples for myself and the Improved Rifleman's Rule gets you closer to the correct answer. I guess that's why they call it Improved.

The best approach is a Ballistic Calculator. Entering the correct information will give you a exterior ballistics solution that's as close as you can get. These use Time of Flight and the component of gravity to determine drop on an angled shot. But you said you don't want to count on an electronic device so that's not going to work for you.

So I think your next best bet would be one of the mechanical slide rules such as the Accuracy First Whiz Wheel. This attempts to put the Ballistic Calculator into a mechanical calculator.

https://www.accuracy1stdg.com/store/itemDetail.cfm?prodID=504

ShtrRdy thanks for the reply to my ballistics question, and the information regarding a mechanical device to act as a ballistic calculator while in the field. I know there is no substitute for acquiring good dope to rely on when shooting longer distances; so I will go with what I have and continue to improvise along the journey. The Accuracy First Whiz Wheel may provide some of the answers I seek.

 

[ShtrRdy]

To help you gain some level of confidence of estimating correction try using an online ballistic calculator like JBMBallistics.com. You can run some different cases to see how much error you would end up with when using the "Rifleman's Rule" and "Improved Rifleman's Rule". Or you may come up with an alternative yourself.

 

[FEENIX]

Some of the newer more sophisticated RFs has the ability to factor in the shot inclination.