Short sight in range

[Jessie]

The 5.56 AR uses the 25m short range for sighting in, what about the .308 ?
What is the common equivalent range for sighting in short range and where downrange will it again be zeroed?
If this was already covered, sorry, but couldn't find it.
I just realized that I forgot an important factor...I'm using 168gr gold medal match.

 

[Tbat]

The .308/7.62x51 trajectory isn't all that different than 5.56/.223, you can sight it in at 25, 50, 100 or 200 meters/yards. Just use whatever suits your needs. I sighted mine in at 50 yards. There will probably be someone along that will point you to some ballistic calculators that will help show the crossovers.

 

[webfarmer]

I use the 50 yard sight in for my M&P 15 which ballistically is good to 220 yards +/- 2" if I recall correctly. But you know, I've never seen that theory applied to the 7.62. Interesting. I sighted my M&P 10 at 100 yards with my Eotech XR 308 and Leupold scope. Would be interesting to know for both the 150 FMJ I shoot and the 168 you shoot (a bullet weight I'd like to start playing with). Good luck!

 

[MichiganScott]

Depending on bullet and velocity, I'm happiest with 2" high at 100 yards. I realize that's not a 25 meter figure, but I've never used the short sight-in method. That will give you about .75" low at 25 yards and close at 200.

 

[copemech]

There is a nice simple calc on the Federal Premium Ammo website.

Basically 50 will get you 200 on both, and an inch or so over at 100.

Sight height above bore measure here would be of a variable than anything as compared to a long gun so input accordingly!

 

[coltle6920]

I used a calculator on Nikon's website.You select your scope and ammo then zero distance and target distance.It will tell you where to aim for what ever distance you are shooting at.

Throwing some random numbers in there I came up with the following...

A .308 zeroed at 25yds using 168gr ammo would put you .03 inches high at 217yds. I have no clue being a complete newbie but I used it to zero my AR15 and the BDC is spot on for me.

Here is a link if you want to play with it...

Nikon Spot-On Program and Tools

 

[Jessie]

Thanks all! Good info and I'll check it all out. Sorry so long to reply.

 

[rojodiablo]

Thanks all! Good info and I'll check it all out. Sorry so long to reply.

For regular BUIS, if you are at 25 with the large aperture, the small aperture will be good at 150yds. If you are at 50, it will translate to 200yds.
The real difference will come when you step beyond 200yds with the 2 rounds. The 308 is heavier, and has a pretty good BC, and the 223 is much lighter, so regardless of BC, it will be affected by wind quicker and to a greater degree.

 

[ChattanoogaPhil]

I used a calculator on Nikon's website.You select your scope and ammo then zero distance and target distance.It will tell you where to aim for what ever distance you are shooting at.

Throwing some random numbers in there I came up with the following...

A .308 zeroed at 25yds using 168gr ammo would put you .03 inches high at 217yds. I have no clue being a complete newbie but I used it to zero my AR15 and the BDC is spot on for me.

Here is a link if you want to play with it...

Nikon Spot-On Program and Tools

That sounds like the trajectory using a typical hunting rile and optic with a sight over bore of 1.5in.

An AR platform will typically have a sight over bore of about 2.5in which radically changes things at a short distance zero. .308 at 25yd zero will be a whopping 8in high at 175yds and cross zero again at about 325yds.

Federal 168 GMM with a 2.5in sight over bore, a 50yd zero results in a much more flat trajectory staying within about an inch of line of sight all the out to 200yds, then it starts dropping. 2.5in at 225, 4.5in at 250, 7in at 275, and 10in at 300yds.

The zero you pick is dependent on the distances you typically shoot.

OP- This is one of the best I have seen with a great many factory loads already setup. Be sure to click advanced option and enter correct data for sight over bore.

Ballistic Calculator GunData.org

As mention earlier, 5.56 and 7.62 trajectory are similar. For an offhand battle rifle it's hardly worth making the distinction.

 

[ironhead7544]

There are a lot of factors involved with this one. It is going to depend on what sight system you are using.

It is best to try it at the distances you want to shoot. Once you have that zero, shoot it at 25 yards and make note of where you hit. You can then check your zero at close range.

When I was in the army, we had the 1000 inch target. You could zero the M16A1 or the M14 rifle with it at 25 yards. The M16A1 sights were high and the zeroing X was about 1 inch below the point of aim. For the M14, the X was above the target about the same distance. The target was a black rectangle that you floated over the front sight. The width of the rectangle was the same apparent width of the front sight and was very easy to be precise with. With is zero, you were supposed to be right on at 250 meters with both rifles. You kept that zero and learned how to hold on the man sized target out to 400 meters. This was with the standard military load at the time.

 

[rojodiablo]

IronHead, I am sure that I came after your time, but suffice to say, the information stayed pretty much the same, sans the M14. We did not handle that except for a few of us who went to advanced shooting/ marksman after the initial range session showed that a few of us had some seasons of hunting and target shooting under our belts.
Basic premise of Rifleman in 1989: Quickly acquire the (man sized) target and put 5 rounds into said target, out to 400 meters.
Basic premise of Marksman: Quickly acquire target, and put 5 rounds into the vital area ring at 600 meters. Beyond this, they were grooming for snipers, which meant a shift in MOS, and very few were asked to make the switch. I might have been able to go, but my MOS was a contract, so I was not interested in switching and giving up the contract..... no contract= Unassigned seaman. ie, deck swabbie.

 

[copemech]

IronHead, I am sure that I came after your time, but suffice to say, the information stayed pretty much the same, sans the M14. We did not handle that except for a few of us who went to advanced shooting/ marksman after the initial range session showed that a few of us had some seasons of hunting and target shooting under our belts.
Basic premise of Rifleman in 1989: Quickly acquire the (man sized) target and put 5 rounds into said target, out to 400 meters.
Basic premise of Marksman: Quickly acquire target, and put 5 rounds into the vital area ring at 600 meters. Beyond this, they were grooming for snipers, which meant a shift in MOS, and very few were asked to make the switch. I might have been able to go, but my MOS was a contract, so I was not interested in switching and giving up the contract..... no contract= Unassigned seaman. ie, deck swabbie.

And with what then? Jesus, I have recently drug out my old SP1 just to see if I can get it to hit a 300, once I work up to it!

Which brings me to another question, the rear flip aparature on it has two holes the same size, one says something like 0-2, the other says 3, both measure something like .072 or something, yet obvious there is some offset between them.

Question is, are there other precision options? Seems the standard now has a large .125 hole and the smaller about the same as the .072 or so?