This is my first time actually posting something, well other than a question a long time ago, so if it's not up to par, forgive me.
I have an ACOG (TA31RCO-A4CP) mounted on my Larue stealth 16" upper. And after searching high and low for measurements on the BDC reticle, I finally decided to try and measure it myself, since I only managed to find one decent post about it on a different site. So here's my not so precise but accurate enough way of going about it. I set up a target on a large piece of cardboard at 100 meters and fired 2 rounds (only had 20 rounds left by this time) at each mark on the reticle that represented 100 meter increments. And yes, even the manual that comes with the optics states that they are designated in meters. Then based on the average elevation dispersion of where the rounds hit, I made a heavy black mark with a sharpie, went back to 100 meters, and did my best to look through and match up each respective mark as kind of a way of verifying everything. Then I went back and took measurements with a measuring tape. Again, these are NOT considered EXACT numbers, but with what I had and how I was going about this, these are VERY CLOSE.
Rifle: LaRue Stealth 16" 1-8 twist upper assembly, double star lower w/ RRA parts kit and standard mil spec trigger, Magpul MOE furniture
Sights: ACOG (TA31RCO-A4CP)
Ammo: Winchester 5.56 55gr FMJ (chronographed @ 3150fps)
Aim Point CM Inches (for those who need it)
1 0 0
2 7.5 3
3 14.5 5.7
4 23 9
5 33 13
6 47 18.5
7 65.5 25.8
8 91 35.8
I took my measurements in cm to the nearest .5cm and then converted them on the computer to the nearest .1 inch. Keeping in mind that this is calculated in meters, here's what those number correlate to in MILS and MOA...
Aim Point MILS MOA
1 0 0
2 .75 2.53
3 1.45 4.89
4 2.3 7.76
5 3.3 11.14
6 4.7 15.86
7 6.55 22.11
8 9.1 30.71
Notice how easy it is using cm and MILS at ranges in meters
It makes life so much easier. Anyway, according to these numbers and using the previously stated ammunition (winchester 5.56 55gr FMJ @ 3150fps), if we assume a G7 BC of .133 (based on Litz's sierra 55gr fmj BC) then we get a corresponding range per mark of...
Aim Point Impact
1 100 meters
2 230 meters
3 315 meters
4 395 meters
5 475 meters
6 565 meters
7 655 meters
8 750 meters
These distances are also rounded to about the nearest 5 meters based on Shooting Lab Ballistic Software and the environmental data for my location (Altitude: 1000ft, Temp: 75 F, Baro: 30.01 in HG, humidity: 45%)
Also, just for the heck of it, I went ahead and ran the numbers for some M855 62gr FMJ @ 2950fps (BC- .151 based on US Army's Ballistic Research Laboratory) and some mk262 77gr SMK @ 2700fps (BC-.190 based again on Litz's findings). Again, these are rough numbers and based on velocities that I've obtained in the same firearm.
Aim Point M855 MK262
1 100 100
2 220 205
3 300 280
4 380 355
5 455 435
6 545 530
7 645 635
8 745 750
So that was my experiment for the day. I realize that the specific model ACOG I have is listed for a 20" barrel but this is the set up I have, I'm happy with it, and now I can use it to it's maximum potential. Hopefully this information helps someone else. It never hurts to test your setup and know for sure what it's doing. If anyone else has done this, please share your findings. More useful information is always welcome
I put all of the numbers on one chart because no matter what I do, when I preview the post, I lose all of the spacing between the numbers. Hopefully it works.
I have an ACOG (TA31RCO-A4CP) mounted on my Larue stealth 16" upper. And after searching high and low for measurements on the BDC reticle, I finally decided to try and measure it myself, since I only managed to find one decent post about it on a different site. So here's my not so precise but accurate enough way of going about it. I set up a target on a large piece of cardboard at 100 meters and fired 2 rounds (only had 20 rounds left by this time) at each mark on the reticle that represented 100 meter increments. And yes, even the manual that comes with the optics states that they are designated in meters. Then based on the average elevation dispersion of where the rounds hit, I made a heavy black mark with a sharpie, went back to 100 meters, and did my best to look through and match up each respective mark as kind of a way of verifying everything. Then I went back and took measurements with a measuring tape. Again, these are NOT considered EXACT numbers, but with what I had and how I was going about this, these are VERY CLOSE.
Rifle: LaRue Stealth 16" 1-8 twist upper assembly, double star lower w/ RRA parts kit and standard mil spec trigger, Magpul MOE furniture
Sights: ACOG (TA31RCO-A4CP)
Ammo: Winchester 5.56 55gr FMJ (chronographed @ 3150fps)
Aim Point CM Inches (for those who need it)
1 0 0
2 7.5 3
3 14.5 5.7
4 23 9
5 33 13
6 47 18.5
7 65.5 25.8
8 91 35.8
I took my measurements in cm to the nearest .5cm and then converted them on the computer to the nearest .1 inch. Keeping in mind that this is calculated in meters, here's what those number correlate to in MILS and MOA...
Aim Point MILS MOA
1 0 0
2 .75 2.53
3 1.45 4.89
4 2.3 7.76
5 3.3 11.14
6 4.7 15.86
7 6.55 22.11
8 9.1 30.71
Notice how easy it is using cm and MILS at ranges in meters
It makes life so much easier. Anyway, according to these numbers and using the previously stated ammunition (winchester 5.56 55gr FMJ @ 3150fps), if we assume a G7 BC of .133 (based on Litz's sierra 55gr fmj BC) then we get a corresponding range per mark of...Aim Point Impact
1 100 meters
2 230 meters
3 315 meters
4 395 meters
5 475 meters
6 565 meters
7 655 meters
8 750 meters
These distances are also rounded to about the nearest 5 meters based on Shooting Lab Ballistic Software and the environmental data for my location (Altitude: 1000ft, Temp: 75 F, Baro: 30.01 in HG, humidity: 45%)
Also, just for the heck of it, I went ahead and ran the numbers for some M855 62gr FMJ @ 2950fps (BC- .151 based on US Army's Ballistic Research Laboratory) and some mk262 77gr SMK @ 2700fps (BC-.190 based again on Litz's findings). Again, these are rough numbers and based on velocities that I've obtained in the same firearm.
Aim Point M855 MK262
1 100 100
2 220 205
3 300 280
4 380 355
5 455 435
6 545 530
7 645 635
8 745 750
So that was my experiment for the day. I realize that the specific model ACOG I have is listed for a 20" barrel but this is the set up I have, I'm happy with it, and now I can use it to it's maximum potential. Hopefully this information helps someone else. It never hurts to test your setup and know for sure what it's doing. If anyone else has done this, please share your findings. More useful information is always welcome
I put all of the numbers on one chart because no matter what I do, when I preview the post, I lose all of the spacing between the numbers. Hopefully it works.
