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Vortex Strike Eagle BDC With Golden Tiger


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#1 Darth Saigus

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Posted 26 February 2016 - 10:08 PM

I'll post this here as a reference.

 

I'm putting a Vortex Strike Eagle 1-6X scope on my Sig556 Russian.  The Vortex AR BDC is set up for the 5.56 obviously so the hashmarks won't be right for the rainbow 7.62x39.  But if properly zeroed the AR BDC can be used out to 500yds very easily.

 

I did the calculations using Vortex ballistic calculator.  The ammunition I chose for my calculations is Golden Tiger.  Based on a BC of .300 and a velocity of 2375 and using a 50/150yd zero, here is what I get.

 

First column is yards, second column is the actual bullet drop, third column is the moa of the BDC hashmarks, fourth column is the difference.

 

100 . +0.9 .-0.0 . +0.9

200 . -1.5 . -2.4 . -0.9

300 . -5.6 . -5.6 . -0.0

400 .-10.9 .-9.5 . -1.4

500 .-17.5 -14.6 .-3.1


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#2 scattergun10

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Posted 28 February 2016 - 09:47 PM

I didn't think 7.62x39 had any drop at 200. I thought it was around 250 that it started. I knew at 300 and beyond it drops like a turd in a well.  



#3 Darth Saigus

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Posted 29 February 2016 - 11:25 AM

All bullets begin dropping the second they leave the muzzle. Gravity: It's not just a good idea. It's the law.

Because of this we generally fire bullets slightly upward so that the bullet will rise to the sight plane, and often above it.
 

A very simple diagram which should help sort it out.

 

Attached File  external ballistics.jpg   44.92KB   1 downloads

 

A complete explanation of external ballistics is a separate discussion but simply search "external ballistics" in Google for more details.

.


Edited by Darth Saigus, 29 February 2016 - 12:33 PM.

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#4 unforgiven

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Posted 29 February 2016 - 01:58 PM

It is surprising how many shooters, hunters and even reloaders have little understand of ballistics.

 

I know avid hunters that know nothing but a hard zero at some specific range.

To them every thing else is just "guess work"

Many folks never shoot over a hundred yards or so, never have much inclination or declination .

 

Unless new shooters study or are mentored by experienced and educated shooters ....they dont get the exposure.

For that matter, lots of older folks that have a lifetime of shooting have never really looked at it.

 

I hope Darths thread sparks some interest here


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#5 InTTruder

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Posted 02 March 2016 - 12:11 PM

I didn't think 7.62x39 had any drop at 200. I thought it was around 250 that it started. I knew at 300 and beyond it drops like a turd in a well.  

Every round drops the instant it leaves the muzzle.  You might have super-elevation for a zero at 100 or 200, but the round has arched upwards and then down to do that.



#6 GunFun

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Posted 04 March 2016 - 02:14 PM

I'll post this here as a reference.

 

I'm putting a Vortex Strike Eagle 1-6X scope on my Sig556 Russian.  The Vortex AR BDC is set up for the 5.56 obviously so the hashmarks won't be right for the rainbow 7.62x39.  But if properly zeroed the AR BDC can be used out to 500yds very easily.

 

I did the calculations using Vortex ballistic calculator.  The ammunition I chose for my calculations is Golden Tiger.  Based on a BC of .300 and a velocity of 2375 and using a 50/150yd zero, here is what I get.

 

First column is yards, second column is the actual bullet drop, third column is the moa of the BDC hashmarks, fourth column is the difference.

 

100 . +0.9 .-0.0 . +0.9

200 . -1.5 . -2.4 . -0.9

300 . -5.6 . -5.6 . -0.0

400 .-10.9 .-9.5 . -1.4

500 .-17.5 -14.6 .-3.1

 

So for quick and dirty field calculations, aim an inch higher than the hash mark per hundred yards after 300. That's easy enough.


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#7 Darth Saigus

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Posted 14 March 2016 - 12:27 AM

I was able to test this to 300yds and found it worked very well for 100, 200, and 300.


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#8 Darth Saigus

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Posted 16 April 2017 - 09:07 PM

I was looking at these numbers again for a range trip today and I realized that I was a bit unclear about the bullet drop numbers.  The bullet drop is in MOA, not inches.  So MOA times range in hundreds of yards gives the actual difference in inches.  Here is a more complete table.

 

I'll post this here as a reference.

 

I'm putting a Vortex Strike Eagle 1-6X scope on my Sig556 Russian.  The Vortex AR BDC is set up for the 5.56 obviously so the hashmarks won't be right for the rainbow 7.62x39.  But if properly zeroed the AR BDC can be used out to 500yds very easily.

 

I did the calculations using Vortex ballistic calculator.  The ammunition I chose for my calculations is Golden Tiger.  Based on a BC of .300 and a velocity of 2375 and using a 50/150yd zero, here is what I get.

 

First column is yards,

.........second column is the actual bullet drop in MOA, 

...................third column is the moa of the BDC hashmarks,

.............................fourth column is the difference in MOA,

......................................fifth column is difference in inches.

 

100 . +0.9 .-0.0 . +0.9  +0.9"

200 . -1.5 . -2.4 . -0.9   -1.8"

300 . -5.6 . -5.6 . -0.0   -0.0"

400 .-10.9 .-9.5 . -1.4   -5.6"

500 .-17.5 -14.6 .-3.1   -9.3"

 


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#9 liberty -r- death

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Posted 10 June 2017 - 09:18 PM

I purchased this scope a couple of months ago and it is my new favorite.
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#10 poolingmyignorance

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Posted 14 June 2017 - 04:17 PM

I do a 25 yard zero, and I'm back on zero at 200 yards with wolf FMJ. I'm not sure the chrono on that round but it's what I have the most of.
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