Angle fire

[Stoopy]

Here:

http://www.ar15barrels.com/data/22dope.pdf" onclick="window.open(this.href);return false;

what is the angle fire table?

[GforceJunkie]

what is the angle fire table?

A correction for when you are firing up or down hill. The steeper the angle, the less you have to correct. For example if your firing down hill (like say from a roof top or ridgeline) and the distance is 100 yards and the angle is 45 degrees. The factor for 45 degrees is .70 So multiply your distance (100 yds) by .70 and you get 70. For this shot, you would dial in your 70 yard dope, not your 100 yard dope. Even though the bullet is traveling 100 yards, because it is at an angle to the earth, gravity is only going to effect it as if it were a 70 yard shot. Not something you need to bother with at our matches.

[AR15barrels]

A correction for when you are firing up or down hill. The steeper the angle, the less you have to correct. For example if your firing down hill (like say from a roof top or ridgeline) and the distance is 100 yards and the angle is 45 degrees. The factor for 45 degrees is .70 So multiply your distance (100 yds) by .70 and you get 70. For this shot, you would dial in your 70 yard dope, not your 100 yard dope. Even though the bullet is traveling 100 yards, because it is at an angle to the earth, gravity is only going to effect it as if it were a 70 yard shot. Not something you need to bother with at our matches.

It's actually better to multiply your DOPE by the correction factor, not the distance used to determine dope.

So if the laser distance is 100yds and your dial for 100yds is say 2 mils, correct the 2 mils by the 0.70 factor, not the 100yds.

[GforceJunkie]

You sure? Show your math! The correction factor is just the cosine of a right triangle formula with the distance being the hypotenuse. Since gravity is straight up and down, we are just figuring out the length of the bottom of the right triangle, the distance that gravity effects the bullet. I get different answers using your method and mine so one of us is wrong. Who is a math wiz and can set us straight?

[AR15barrels]

If you input the firing angle into a real ballistics calculator and then use the method of adjusting dope and the method of adjusting distance, you will find that adjusting dope is more accurate.
Ryan and I hashed this out in a thread afew years ago and I was arguing the same as you, but he was right...

Time of flight plays into it, but adjusting the distance to target shortens time of flight without accounting for the bullet actually traveling the full distance.
Adjusting the dope creates a different correction that's closer to real world.
An actual balistics calculator soution with an input for the angle is the most accurate method of all.

[GforceJunkie]

I think your right, using the cosine on the distance would work if the bullet flew in a straight line. Your method takes into account more of the parabolic nature of a bullet flight, but as you said, it is not correct either, just closer. And how close depends on the exterior ballistics of the bullet, everyone will be different. The only real way to get a solid number would be a computer program that took all the perameters into account. I should split this off to its own thread...

[AR15barrels]

I should split this off to its own thread...

Done.

[AR15barrels]

Another small reason to adjust the dope and not the distance is that you want to be using the wind call for the actual distance the bullet travels.

If you were adjusting the range to target and then looking on your range card, you have to look at two different distances to determine the elevation and wind dials.
By using the actual distance to target, you calculate the elevation and use the wind as the card calls out.
Looking at two different distances on the card just adds more chances to fuck up dialing your scope, even though it is easier to correct the distance than the dope.

[GforceJunkie]

Ok, can we get ASR to build us a repelling tower so we can add high angle shooting to our matches?

[Stoopy]

Ok, can we get ASR to build us a repelling tower so we can add high angle shooting to our matches?

That would be fun. Shoot at the top then have to repel down and shoot again.

[Gnzrme]

I can just hear Ed's comment on that...

[Teletiger7]

Buy an angle cosine indicator if it really bothers you.

[rksimple]

Good read on the subject:

http://www.exteriorballistics.com/ebexp ... icle1.html" onclick="window.open(this.href);return false;