Sighting in a New AR15

[Winkman822]

It's been quite a while since I've been on here due to other life commitments, but now I'm hopefully going to be back more regularly. That said, I treated myself to a new Stag Arms 3G and an EOTech 512-A65 a couple weeks back. Just so this doesn't turn into a debate about optics, I picked the EOTech because with my eyesight and astigmatism, I found the EOTech reticle to be much easier to acquire than the offerings from Aimpoint or Trijicon (the Reflex not the ACOG).

Anyway, the Stag is chambered for 5.56, but as we all know, the 5.56 rifle should also be able to use .223 ammo. I plan to run primarily 5.56 ammo in this rifle, but to shoot 5.56 I have to go to my outdoor range which is currently on very limited operating hours due to the time of year, and since I still like to do some rifle plinking over the winter (and because I have some new gear), I'd like to get this rifle sighted in sooner (i.e. this week if possible), rather than later. I plan to shoot 5.56 55 gr. XM193 as my primary ammo in this, but for the time, being restricted to my local indoor range, I'm restricted to .223 55gr. frangible ammo. How bad would it be to initially sight my rifle for the .55 gr. .223 and then make some adjustments come springtime for the slightly hotter 5.56 round?

 

[Sam1911]

You'll likely be pretty close. On paper, certainly.

 

[Winkman822]

I figured it'd be close given the same bullet weight. I suppose I'll give it a go this weekend and then make some fine tuning type adjustments for the 5.56 round come better weather.

 

[gotigers]

Sight in with what you can now. Like said above, the two will be very close out to 50 yards. When it comes time to shoot 5.56, you'll be on paper for an easy rezero.

 

[TexasPatriot.308]

just like we did in the military 42 years ago..."combat zero" Google it and try it, it will work.

 

[Rudedog]

With that sight, the ammo and the distance your talking about, when you zero with one load you'll be really close with any other load even out to 100 meters.

 

[TexasPatriot.308]

the military aint been wrong on this....the way you sight in a combat rifle.

 

[Warp]

They two will probably be darn close

 

[Hardtarget]

Even if the zero is a bit different...isn't that part of the fun of shooting? You get to tinker with the rifle. Learn a bit more of the riflemans skill. Shoot a bit more. Sounds like a good day at the range to me!

Go shoot! Have fun.

Mark

 

[gotigers]

You probably won't notice a difference. In 3 gun, I shoot bulk 55gr at everything 100 yards or less. Then 77gr handloads for everything over 100 yards. Sure there is a difference, but I don't really have any issues with bullet drop. I have more of an issue with accuracy past 200 yards with the 55gr than with bullet drop. The handloads are much more precise. I guess that goes without saying, but my point is, I wouldn't worry about it too much unless you are going for small groups out past 200 yards.

 

[Sam1911]

the military aint been wrong on this....the way you sight in a combat rifle.

He's not asking about how to establish a combat zero, but about differences in point of impact between a .223 frangible load and a 5.56Nato ball load.

The military aint been issuing .223 Rem frangible ammo to sight in with.

 

[Winkman822]

Well Looks as though the biggest difference would be bullet weight, and going from what y'all are saying is that the 55 gr. .223 2ill be as near the 55 gr. 5.56 XM193 that only very minor adjustments will be needed when it comes time to get to shooting the 5.56 regularly.