Need advice on a scope

[Bushwack44]

I've finished an AR 6.5 Grendel build and I'm about to mount a Nikon Prostaff 4.5-18x40 on it (reticle below). The AR will be used strictly for shooting steel from 200 - 600 yards (Angeles Range). All other scopes I have on AR15s I've zero-ed at 100 yds. As I'll only be using this AR (scope) for distance target shooting, should I try and zero this scope at 200 yds?

I'm not a competition shooter. It's just fun time at the range when I go. But I don't recall reading/anyone mentioning having their scope sighted at 200 yds for long distance shooting. Is doing so practical? Will it make using the reticle more difficult (for accuracy)?

[Droppin Deuces]

Use a ballistics app to adjust your curve to match your reticle as much as possible. This is the reason I don't care for BDC reticles, but I understand some people just don't have the option or don't want to be bothered with a conventional ranging style reticle. The best thing you can do is either what I suggested above, or better yet, if you are loading your own ammo, adjust your muzzle velocity to match the reticle as much as possible.

If you want to be accurate at 600, figure out your close and far zeros and start by zeroing close. A common example would be the 25/300 zero with .223/5.56.

[Bushwack44]

Use a ballistics app to adjust your curve to match your reticle as much as possible. This is the reason I don't care for BDC reticles, but I understand some people just don't have the option or don't want to be bothered with a conventional ranging style reticle. The best thing you can do is either what I suggested above, or better yet, if you are loading your own ammo, adjust your muzzle velocity to match the reticle as much as possible.

If you want to be accurate at 600, figure out your close and far zeros and start by zeroing close. A common example would be the 25/300 zero with .223/5.56.

Using Nikon's app, it seems if I zero at 200 yds the lowest reticle gives me a farther range (572 yds) then if I zero at 100 yds (lowest reticle showing 522 yds). I know the app isn't an exact science. Maybe I'm over-thinking?

[Droppin Deuces]

What ammo are you using?

[Bushwack44]

What ammo are you using?

Hornady Black 123gr ELD Match

[Droppin Deuces]

Here's what I get using that ammo with the box indicated muzzle velocity and a 200 yard zero. 12" target at 600 yards on 18x mag.

You're pretty darn close. Just a few clicks away.

Not sure if you can see it, but the close zero is indicated as 42 yards. You'll probably want to go .5" down to get your impact right on top of the post.

[Bushwack44]

I was playing around with the Nikon app. Here's what I came up with (at 200 yds zero):

[Droppin Deuces]

Yeah, I'd say it looks like you'll be pretty close

I used the G7 BC model, so that may be causing some differences if you used the G1. But yeah, .5" between the two at 600 is still pretty darn close. Please report back with your actual results! I always like to get an idea of how accurate these apps are.

[JMP]

There isn't a whole lot of difference between a 100 yard zero and a 200 yard zero in most rifle cartridges. Because the scope is mounted above the rifle, the trajectory may still be at a slight upward tilt at 100 yards and it will drop a bit at 200 yards often making the two zeros just an inch or two apart. It depends on your bore height, velocity, and other factors. With a BDC, just use what feels comfortable and convenient.

[Droppin Deuces]

^^^That could be the difference. I just assumed he's shooting an AR and I entered 2.5" height over bore. If I enter it like a traditional bolt action layout, it lands 10 yards shorter.

[Bushwack44]

^^^That could be the difference. I just assumed he's shooting an AR and I entered 2.5" height over bore. If I enter it like a traditional bolt action layout, it lands 10 yards shorter.

Hmm...I used 1.5" height as that's the default setting on the Nikon app (I am shooting an AR).

What's the difference between G1 and G7 (I had used G1 for my data as that was the default setting).

[Droppin Deuces]

Hmm...I used 1.5" height as that's the default setting on the Nikon app (I am shooting an AR).

What's the difference between G1 and G7 (I had used G1 for my data as that was the default setting).

It's just an updated model that tends to give better results in longer range shooting. The g1 is based on an old style of bullet where the G7 is based on the more slippery profiles that are available now.

I'm sure there's more to it than that, but I don't know what the other differences are. I tend to get some distance taken off the end of my readings when I enter the G7 BC.

[Droppin Deuces]

Here you go:

http://www.bergerbullets.com/a-better-ballistic-coefficient/

[Bushwack44]

Here you go:

http://www.bergerbullets.com/a-bette...c-coefficient/

Good read.