diff bullet drop 'scales'-re ACOG

[Klunk]

Hey,

over a few hundred meters (say 600) how much of a difference is there in bullet drop between 7.62 nato 7.62x39 7.62x54 and 5.56????

have been having a discussion pertaining to ACOG scopes with bullet-drop compensators and just how much diff there is between certain calibres over the 600-800 meter range scale...

like/example:

using a 7.62NATO scope on a 5.56 rifle....how much 'off' will the drop reticle be?????

 

[Glock4ever]

Depends on the load. ACOGs are have reticles for specific loads (i.e. 5.56mm NATO M855) you would need to select a reticle and then to run the comparison run that load through the ballistic calculator. You can than compare the drop to the output of the specific load of 5.56mm that you want to shoot. Up close (<300m it shouldn't be too far out). That being said what you can do is take the reticle information (i.e. the number of MOA/Mils that the reticle is set for at 300m) and apply it to your load but it would only be accurate at the true correct distance - in this case the 300 hash mark may correspond to 345m for the 5.56mm. It sounds complicated but it really isn't that big of a deal - if you look at the Boone and Crockett Reticle for Leupold you can see how the various hash marks don't necessarily translate to 1/2, 3, 4, 500m but can actually be different distances depending on the drop of your bullet and if you play with the magnification you can actually have it correspond to different drops (hence why the varmint reticle from Leupold has two settings on the mag dial for the different types of loads available). This only works on SFP scopes...

 

[Juster]

"Off" isn't the word for it. 12 foot in these random examples.

 

[Ar180shooter]

Depending on what load the ACOG is calibrated for, if you handload, you may be able to develop a .308 load that has a similar trajectory to the 5.56 the reticule was designed for. Mind you, I haven't tried this, so I have no idea how well or even if it would work. I'll also note that unless I'm mistaken, trijicon makes ACOGs calibrated for 7.62 NATO cartridges too.