Range Report Bullet Drop Using a Mil-Dot – Calculations vs Range Results – Need Help!

[p712k]

This is the first time I have tried to do this and the range results I am getting do not match my calculations. If anyone could point me in the right direction it would be be greatly appreciated!

I need to verify my holdover calculations I made for a mil-dot reticle, unfortunately the longest range I have access right now is 100 yds. I used a large target and fired groups trying to simulate the distances at each range, I know it not exact but I was hoping to be able to at least roughly verify my math.

I used an online calculator to get the ballistic information. I am using SSA 5.56 77gr BTHP ammunition.

It gave these results:

Range Velocity Impact Drop ToF Energy
000 2700 -2 0 0 1246
100 2459 0 2.78 0.12 1034
200 2237 -3.79 11.34 0.25 856
300 2026 -14.58 26.91 0.39 702
400 1828 -33.88 50.99 0.54 571
500 1644 -63.67 85.55 0.72 462

I wanted to figure out the holdovers at each range so I divided them by the size of a mil at that distance, from this I got:

Size of mil
at distance Exact mil Rounded mil
100 0 3.6 0.0 0 Mils
200 -3.79 7.2 -0.52639 ½ Mils
300 -14.58 10.8 -1.35 1.5 Mils
400 -33.88 14.4 -2.35278 2.5 Mils
500 -63.67 18 -3.53722 3.5 Mils

I then marked this on a drawing of a mil-dot reticle.

I then went to the range and fired groups on a large target placing the POA at the locations on the reticle indicated for each distance. The results I got do not make sense to me.

The height of the groups to the POA are as follows:
500 (simulated) – 12.5”
400 (simulated) – 9”
300 (simulated) – 5.25”
200 (simulated) – 2”
100 (actual) – 0.0”

Now these numbers do not look anything like anything in my previous calculations. Are they off? Do I have to do an additional calculation to check them? Are my calculations wrong?

 

[hamstur]

Thats correct where they hit. Take your simulated 500 yard dope of 3.5 mils.

3.5 mil @ 100 x 3.6" per 100 = 12.6" at 100 yards

If that were really 500 yards away, you would have been aiming 12.6" @100 x 5 = 63" above target

Your actual exact above is listed as 63.67"

You just need to multiply your 100 yard POI measure by the # of 100 yards you are simulating to get the total simulated drop.

 

[p712k]

Thanks!

Looks like it is correct, I think any errors in the holdovers were probably human.

12.5*5 62.5 -63.67
9*4 36.0 -33.88
5.25*3 15.75 -14.58
2*2 4.0 -3.79

Thats correct where they hit. Take your simulated 500 yard dope of 3.5 mils.

3.5 mil @ 100 x 3.6" per 100 = 12.6" at 100 yards

If that were really 500 yards away, you would have been aiming 12.6" @100 x 5 = 63" above target

Your actual exact above is listed as 63.67"

You just need to multiply your 100 yard POI measure by the # of 100 yards you are simulating to get the total simulated drop.