What is the difference between the  A1 and A2 front sight?

round and square

Quoted: round and square

A1 is round and has 5 adjustment notches. A2 is square and has 4 adjustment notches.

Thanks,why would my upper have A1 front sights and A2 rear sights?

Quoted: Thanks,why would my upper have A1 front sights and A2 rear sights?

Why not? IMO, A1 front sights are better. They are capable of a more precise adjustment.

pictures help since most are not psychics


you could have an a1 bbl. or previous owner installed it

One sucks one doesnt.

There is no logical reason why a company would put an A1 front sight on an A2 sighted rifle.  Through some freak of a chance, maybe one was in the parts bin.

Opinions as to which is better go back and forth.  If you understand the reason for the change, then you can make a choice.  A round front sight post does not give quite as sharp an image as a square profile.  Light reflecting and bleeding around the curve.  So an A2 square front sight post will give you a sharper image, resulting in increased accuracy, assuming you are good enough to make use of the potential.  A round, A1 type has a finer adjustment, because it has 5 detents vs. 4.  Take your pick.

They ran out of A2's and installed A1's?


The 5 notches on the round A1 post give 1 moa adjustments (1.000something inches at 100 yds).

The 4 notches on the square A2 post give 1.25 moa adjustments.

The round A1 post can cause difficult sighting when the sun is to one side, the post appearing light on one side, darker on the other.

The square A2 post gives a sharper image.

I have had both on my rifles, and the A2 is the better post in my opinion.

Even if your rifle's upper is A1, I advise changing the front post to the square A2, and the rear aperture to the A2.  These will install easily in place of the A1 parts.  While you have the rear sight apart, exchange the A1 windage drum for a Rapidex Windage Knob.  This has 1/2 MOA clicks.  It is easily adjustable, but not likely to be "bumped" and accidently change settings.  It would require deliberatly grasping the knob and turning.

There are numbers on the knob, and you can memorize the setting.

The A2 rear aperture has the larger 0-200 aperture, and the small long range aperture.  The large hole is much better for most shooting, quicker to get the sight picture, and especially better if you must use it at dawn/dusk or night.

Quoted: They ran out of A2's and installed A1's? The 5 notches on the round A1 post give 1 moa adjustments (1.000something inches at 100 yds). The 4 notches on the square A2 post give 1.25 moa adjustments. The round A1 post can cause difficult sighting when the sun is to one side, the post appearing light on one side, darker on the other. The square A2 post gives a sharper image. I have had both on my rifles, and the A2 is the better post in my opinion. Even if your rifle's upper is A1, I advise changing the front post to the square A2, and the rear aperture to the A2.  These will install easily in place of the A1 parts.  While you have the rear sight apart, exchange the A1 windage drum for a Rapidex Windage Knob.  This has 1/2 MOA clicks.  It is easily adjustable, but not likely to be "bumped" and accidently change settings.  It would require deliberatly grasping the knob and turning. There are numbers on the knob, and you can memorize the setting. The A2 rear aperture has the larger 0-200 aperture, and the small long range aperture.  The large hole is much better for most shooting, quicker to get the sight picture, and especially better if you must use it at dawn/dusk or night.

+1 Good Info