Sight in for AR-15, M1A

R

Ray HP

New member
I need some help to prepare my sons for High power competion at 200yds. We will be sighting the rifles at 100yds. I need to know how high should the impact be at 100yds to be good at 200yds.

Both rifles are using generic ammo.
 
If you have A2 sights on the AR, set you elevation knob down 2 clicks below the 8/3 bottom setting (you may have to reset where your elevation bottoms out, it might not go to 8/3 bottom -2), and zero the rifle using the small peep at 50yd. You will then be zeroed at 200m (220yd). This works for M193 55gr and SS109 62gr ball.

Somebody else will have to help you with the M1A.
 
Per My Sierra book's ballistic tables:

The .223, at 1-3/4" high at 100 yards, is dead on at 200. This is for a 55-grain Spitzer, MV 3,000 ft/sec.

The .308, at 2" high at 100 yards, is dead on at 200. This is for 150-grain Spitzer, MV 2,700 or 2,800 ft/sec.

There might be variations of 1/4" or so, as a function of the ammo or the barrel length. It oughta pretty well hold true for the center of a group.

Hope this helps,

Art
 
If you plan on shooting "across the course" (200, 300, and 600 yd.) then standard A2 sights might not go up enough. Plan to zero the rifle with the front sight as low as possibe so that you can get the most out of the rear elevation.
 
Not enough elevation? AR15 sights go to 800 meters and M1A sights go out to 1200 meters. That ought to cover 600 yards. Or are you talking about readjusting the where the rear sight bottoms out?
 
Art Eatman

Thanks for the info. Can I impose on you to look up the same info for a 168 grain HPBT match round for the M1A?

Thanks,

Ledbetter
 
Thanks Schmit

But I don't know what to put in for "Ballistics co-efficient." I'll revisit and give it another try. Appreciate the reply.

Regards.
 
Thanks for the help,it is greatly appreciated. My origional goal was to have enough information to score a 7 or 8 and make adjustments from there. Art's answer was more precise than I ever imagined possible.

Thanks again for the help.

Ray
 
Q-Man, I have not seen a standard A2 that would go up to 600 yds. The stop short, about 500 or so. Match sights will go to 1000 yds or more.

Ray, plan on roughly 3 minutes elevation change from 200 to 300 and about 3 minutes for each hundred + 1 more at 600...at least with standard 80 gr. loads. So depending on sight manufacture (most match sights are 1/4 minute now, my Rock River sights are weird...1/3 minute) you'll be adding 30 to 40 clicks up. This will at least get you on paper...your pit man will tell you the rest.
 
This is a picture of the sights on the carry handle on an M4 carbine. They go from 300 meters to 600 meters as is indicated by the 6/3.
Carry_handle_elevation_knob.jpg


This is a picture of the rear sight of an M16A2. They go from 300 meters to 800 meters as is indicated by the 8/3.
ara2rsa.jpg
 
The numbers stamped have not matched the hits I have seen...that's all. I've seen several guys with their rears cranked all the way up ans still hitting quite low. As I stated before, perhaps the front sight needed to go down. I will repost my previous message.

If you plan on shooting "across the course" (200, 300, and 600 yd.) then standard A2 sights might not go up enough. Plan to zero the rifle with the front sight as low as possibe so that you can get the most out of the rear elevation.
 
I finally see what you're saying. Sorry. I guess I'm showing that I haven’t done any serious shooting at that range and just assumed that the number on the elevation was correct. Is your experience with heavier bullets than SS109/M855 or M193?
 
I'm sorry, as a non-military shooter (my only experience shooting a real M16 in the military was in Air force Basic Training...for one day), I have no idea what the SS109 and others are. I know that they're military match rounds. What most civilian AR guys shooting Highpower are using is 69 gr Sierra HPs at 200 and 300 yds, and Sierra 80 gr HPBT for 600. There are some other 80 gr. VLD (Very Low Drag) bullets out there, but I don't know the names. I have not ran into any military shooters from my area. I'm developing loads for the Sierra's right now. I just switched to using an AR from using the M1A and M1 Garand, so therefore, load development.
 
I gotta check another book to see if it has the 168-gr HPBT. The 165-grain Spitzer BT, at 200 yards, won't be much different.

Per Mr. Sierra, 2-1/4" high at 100 yards should be dead on at 200 yards, for a MV of 2,600 ft/sec. Other muzzle velocities: 2,700 ft/sec, 2" high; 2,500 ft/sec, 2-1/2" high.

I didn't mention it before because it just came to my attention from further looking at the book, but all these numbers are for a line of sight 1-1/2" above the bore. (Typical scope mount height)

If your line of sight (AR 15, iron sights) is higher, my data will have higher impact points at 200 yards than what I've given you; "guesstimate" accordingly.

Isn't it common at most matches to have some limited number of sight-in shots?

Art
 
Art, you get 2 sighters per position in NRA Highpower. IOW, not enough if you're not already on the paper. However, if you can get on paper with your first sighter, calculate and adjust, fire again, calculate and fine tune, you should be on...assuming the wind isn't kicking your butt from all directions.
 
From 100 to 200, if you're not on the paper you have some serious problems. Just go up 2 MOA and take your sighters from prone, then adjust from there.

It also really helps a lot if you can accurately call your shots--high, low, left, right, and how far from intended point of aim. Then when your sighter should have hit the edge of the 10-ring at 2 o'clock but the spotter shows a center X, you'll still be confident in your sight adjustment.

Eventually, you can shoot one, adjust, shoot #2, adjust if needed, and go from there.
 
Cheapo, exactly what I was saying. If you're doing your job when the rifle goes off, you'll know where the sights were at the exact moment of ignotion. If you're shot's way off, then you know it was your sights that need adjustment. It's that instant sight picture that helps you get your sighters tuned in.
 
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