Hello All,Iam new to the board and to the sport of AR-15 Rifles so bear with me .

Went to the range and sighted in the Bushmaster with the A2 sight. Sighted in at 25 yrds.( as per the manual) with the elevation knob 1 click up from the 8/3 mark on the knob. Adjusted the front site up a click to correct and it is dead nuts.
Went to the 100 yrd. range turned knob back to the 8/3 mark,( as per the manual)and it is about 5 inches high from bullseye.

I guess my question is Why does the elevation knob start at 300 meters and not at least 100 meters ? How are you to sight the rifle in at anything less than 300 meters ? It just seems useless to have the elevation start at 300 meters and go all the way up to 800 meters !

I for the life of me couldn't imagine cleanly hitting anything (man size target)beyond 300 meters with the open sights let alone have the adjustment for up to 800 meters .

     THANKS !

The trajectory of a 5.56mm round from a battle-zero of 25 yards to a target at 300 yards has much less than a 5" variance.  Ergo, sighted in at battle-zero you will hit from point of aim to a few inches above at any range from 25 to 300 yards.  The Swedes used the same idea in their turn of the century infantry rifles.  The infantrymen only had to aim at the beltbuckle all the way out to 600 yards.  M96 Swedish mauser is what I am talking about here, but I degress...

This is a battle weapon, if you want to plink bullseyes at 100 yards, put a scope on it.  Mine shoots a little high at 100 yards as well.  Not 5 inches mind you, only an inch or two, depending on load.

It might take some getting used to if you have never shot with a peep sight before, but you can definately hit man-sized targets at 300 yards and beyond.  Just don't try to learn to shoot with a peep all at once, you'll give yourself a migraine!  

boltman has a good point there "Just don't try to learn to shoot with a peep all at once, you'll give yourself a migraine!"..
also, WELCOME.
HUNTER FROM ARGENTINA
OUT.

I gotta say, I just got my AR kit and put together my first AR.  Checking out the sights, the large aperture is HUGE!! .. even the small aperture is pretty damn big.  I thought they'd be a little smaller!  

Gotta get a couple mags and some ammo then go sight 'er in.


(edited to add:)
I thought I'd read somewhere that the trajectory of the 5.56 will rise about 9 inches between 25 and 300 yards... I could be mistaken, of course!

The idea of zero at 25 METERS at 8/3 +1 has pretty much been discredited.  It doesn't work, the trajectory is way to high.

Now there are ways to set the sight up so you have a 100 & 200 meter zero along with the others.

You will need to reset your elevation dial so it bottoms out 3 clicks BELOW the 8/3 setting, then zero at 50 yards with the sight set at 2 clicks BELOW the 8/3 setting (we call this 8/3 -2).

After you are zeroed (ALWAYS USING THE SMALL APERTURE) you set the sight to 8/3-3 (bottomed out) for 100yard shooting and 8/3-2 for 200 Meter shooting, and the numbers on the dial for what ever distance you want to shoot at.

For more details on zeroing your rifle I suggest a visit here:
communities.msn.com/TheMarylandAR15ShootersSite&naventryid=120
I really recommend the Santose Zero.  Its the most accurate.

Quoted: I thought I'd read somewhere that the trajectory of the 5.56 will rise about 9 inches between 25 and 300 yards... I could be mistaken, of course!

Only if you try to zero at 25 yards.  But then again if you zero at 25 yards you will be over 11" HIGH at 300M.

Folks the 25M zeroing was intended for the M16A1 which has a different sighting system.  When they tried to bring it over to the A2 it was screwed up "big time".  Instead of 8/3+1 the rear sight should be set to '4' for rifle or '4+2' for carbines if you want to zero at 25 yards.

Forest

'4+2' for carbines if you want to zero at 25 yards

Do you mean turn the rear to "4" once then go all the way around to "4" a second time?

If so, is one supposed to zero at 25M at this point?

Quoted: Hello All,Iam new to the board and to the sport of AR-15 Rifles so bear with me . Went to the range and sighted in the Bushmaster with the A2 sight. Sighted in at 25 yrds.( as per the manual) with the elevation knob 1 click up from the 8/3 mark on the knob. Adjusted the front site up a click to correct and it is dead nuts. Went to the 100 yrd. range turned knob back to the 8/3 mark,( as per the manual)and it is about 5 inches high from bullseye. I guess my question is Why does the elevation knob start at 300 meters and not at least 100 meters ? How are you to sight the rifle in at anything less than 300 meters ? It just seems useless to have the elevation start at 300 meters and go all the way up to 800 meters ! I for the life of me couldn't imagine cleanly hitting anything (man size target)beyond 300 meters with the open sights let alone have the adjustment for up to 800 meters .      THANKS !

You can be amazed at what you can hit at 400 meters, give yourself the benefit of the doubt. It starts at 300 because the dial is for the small or long distance aperture, when it is at the 300 m mark the large or ghostring works up to the 200 m range, and the santose way, hey, Im an A1 dude.
GG

Assuming this is your first time shooting an AR.  Here are some other tips...It makes it alot easier if you make sure you are focusing on the front sight post-not the target or the rear sight.  Also, try the flat tire method-this means instead of trying to get the top of the front sight post centered on the rear aperture, leave a little room and make it look like a flat tire.  Whatever sight picture works for you, just make sure you make it consistent.  You can hit a man target at 500 yds. with this weapon easily with practice. The link Forest gave is a great one-especially the improved battle sight zero method.

GOATBOY - get the Santose zero on this site - PLEASE!!!!

Undercut - I was a helluva lot higher at 100 than you till I learned that the mil manuals are **wrong**.  Drove me f*cking crazy.  Good company/batallion commanders are having their troops sight in using this method.  Follow Forest's advice and go to the Maryland site.

Tate

I thought 8/3-2 was 2 clicks from 8/3 you said 3.  I'm confused.

The zero method Forest described, 8/3-3 clicks, is commonly called USMC zero. The Santose method bottoms out the sight at 8/3-2 clicks.

Either one is good for short range shooting. Use the small aperture. The large aperture is a battle sight (essentially a ghost ring) and not generally used for target shooting.

UNDERCUT, try this. Turn the elevation wheel CW all the way up. It should stop 2 or 3 clicks past the 8/3 mark. That's the factory setting for A2 sights.

What you want to do is adjust the allen screw (instructions are on the Maryland shooters website) so you move those extra 2 or 3 clicks from the top of the scale to the bottom of the scale. That will enable you to bottom out the elevations wheel below the 8/3 mark to shoot at 100 yard ranges.

Then when you adjust the elevation wheel up, it should stop at the 8/3 mark at the top of the scale instead of going past it. HTH

Man, you guys have got me totally confused here but this looks right to me:

You will need to reset your elevation dial so it bottoms out 3 clicks BELOW the 8/3 setting, then zero at 50 yards with the sight set at 2 clicks BELOW the 8/3 setting (we call this 8/3 -2).

After you are zeroed (ALWAYS USING THE SMALL APERTURE) you set the sight to 8/3-3 (bottomed out) for 100yard shooting and 8/3-2 for 200 Meter shooting, and the numbers on the dial for what ever distance you want to shoot at.

Skipper, go to the link Forest gives above (Maryland Shooter's Site).  There you will find many zeroing methods including the USMC you just described.  Also, you will find the "improved battlesight zero" (Santose Method).  This is a very good, easy to follow method.

Quoted: Forest '4+2' for carbines if you want to zero at 25 yards Do you mean turn the rear to "4" once then go all the way around to "4" a second time? If so, is one supposed to zero at 25M at this point?

You will find you CAN't go to 4 a second time.  

4+2 indicates you set the dial to 4, THEN go up 2 more clicks.

Not at 25M this one is for 25 YARDS.  Subtract 1 click if you want to do this at 25 Meters

Quoted: The zero method Forest described, 8/3-3 clicks, is commonly called USMC zero.

No its not.  Nobody in the Military zero at 50 yards.  LTC Santose came up with this method orginally for M4 carbines on civilian ranges (since civilians typically have 50 yard positions on their ranges.

The USMC zero is different.  The only thing they share is the ability to click BELOW 8/3.

Quoted: I thought 8/3-2 was 2 clicks from 8/3 you said 3.  I'm confused.

Don't be confused its EASY.  Just go to the link I provided above and follow the simple step-by-step instructions.

Quoted: Quoted: The zero method Forest described, 8/3-3 clicks, is commonly called USMC zero. No its not.  Nobody in the Military zero at 50 yards.  LTC Santose came up with this method orginally for M4 carbines on civilian ranges (since civilians typically have 50 yard positions on their ranges. The USMC zero is different.  The only thing they share is the ability to click BELOW 8/3.

I stand corrected. USMC zero is at 25 meters, not 50 yards. Gives you a 300 meter battlesight zero. What you described above is actually a mix of the IBZ and USMC zero. Thanks for noting that.

Quoted: I stand corrected. USMC zero is at 25 meters, not 50 yards. Gives you a 300 meter battlesight zero. What you described above is actually a mix of the IBZ and USMC zero. Thanks for noting that.

Actually if you follow the USMC zeroing instructions 8/3+1 at 25Meters you *WILL NOT* have a 300M battlesight zero.  The round will be hitting around 11" HIGH at that range.  That is why I recommend people follow the Santose IBZ over the standard Military method.