All the pictures I've seen with an Aimpoint mounted on the top of an AR, they seen to be using the front sight along with the scope to aim.

I've never got a chance to peer down one of those Aimpoints.  Obviously you need two different points to aim a rifle.  Am I correct in assuming that the scope is used in conjunction with the front sight to aim?

This would make sense but leads me to other questions:  Is the rear sight (flip up) used in conjunction with a red dot scope?  What is the benefit to having a flip up front sight if it is always being used to aim?

By the way, all of this takes place on the top of an A3 flat top upper.  Thanks for all the help again.

No with the red dot - you put the dot on the tgt, the front is immaterial (for this point).
That is the nice thin with Red Dots you dont nedd two points of aim.

 Fixed fronts are tougher - and do not require any armorer work which is why the Armed Forces use them.

the flip-up rear sight is a backup sight. As you know, any electronic device will fail for any reason or even be out of battery for a long time use. Usually, you flip it down as red-dot sight is using.

So from what you tell me:

1) The fixed iron front sight will not get in the way while using a red dot scope.

2) If a red dot fails, just remove it, flip up the rear sight, and keep going.

Right

It the failure is battery related and the scope it is mounted right, you do not even have to remove it.  Just look through the scope.

I adhere to the KISS principle and don't use [i]flip anythings[/i] on weapons.  Mount a fixed rear sight behind your Aimpoint.  Push the Aimpoint as far forward as you can.

If properly mounted the Aimpoint CompM-series will have the dot positioned right at the tip of the front sight when looking thru the iron sights.  This provides an identical battlesight for both sight systems.  It's also the way to set a preliminary zero on the rifle.

When using the dot both eyes are open and the iron sights are simply ignored -- you won't see 'em.  Whereever the dot appears is where the bullet will go (once you're zeroed).  As noted above if the dot fails -- or you forget to turn it on (don't ask!) -- you just use the irons and squeeze the trigger.

Flip rear sights will cost you points at a match.  They have more severe consequences in the rear world.

-- Chuck

Chuck, you just nailed something thats been bugging me. Ive been reading trying to figure out my optimal configuration for a flat top. Until now Ive been set on flip sights. What would you (or anyone else with experience with 'em) recommend as a ((solid)) fixed rear modular sight? Thx, NW

funny. i've got flip ups on my flattop upper. got a couple thousand rounds through it and it's held up well. of course... i don't and never will treat my AR like the A2 i had in the army.

:) chris

There is no sense of having a rear iron sight in the way of a red dot if the red dot is what your aiming with. A fold down rear iron like the #40 can be there as fast as you need it if thae battery starts to die.
Good Shootin, Jack

The rear sight is [i]not[/i] in the way of the Aimpoint CompM-series if the sight has been properly mounted.  None of the sights are visible, the only thing is that little dot floating out there.

The best rear sight for behind the Aimpoint is the one that comes on the detachable handle.  Hacksaw, belt sander, and a bit of Aluminum Black and you're good to go.  The little Diemaco plastic C8A1 rear sight is pretty good too.

Positioning the dot away from the eye, and the rear sight is required.  On a flattop push it to the front of the rail and use the GGG cantilevered mount.  On the SIR System (or similar) it can be mounted right behind the front sight.

On a handled receiver -- remember KISS? -- mount the sight over the handguards on either the Aimpoint Forward Mount or the ARMS #39A2Plus.

If you're trying to sight the dot -- cheek weld and all -- you'll probably got your head too low as well as the sight.  The iron sights should appear in the lower section of the Aimpoint.

And, no, you can't flip a rear sight up as [i]fast as you need it.[/i]  If it ain't there when you need to pull the trigger you're out of luck as both hands are occupied.

Remember I'm talking about weapons and uses where the targets shoot back.  [;)]

-- Chuck

I just put a S.I.R. on my AR.  There seems to be a little space right behind the top rail on the S.I.R.  Seems that gap needs to be filled with a rear sight.  It looks like a #40 rear flip up will fit in there nicely.  I was not aware there was a fixed rear sight to place back there.  Where can a guy pick up one of these?

Thank you for all the input.

Only the 40 fits there but you could just leave it in the up position. [;)]

I have not heard of any US soldiers dying because they had to go to the KAC 300m sight on the M4 and it was too slow to get into action.  Reloading takes longer than rear sight deployment.

If you have a SIR System about the only thing that fits is the flip sight.

I've no problems with flip sights that don't need to be flipped -- if they're up all the time they're ready to go.  Problem is getting the sight up when you need it [i]right now[/i].

Fine motor skills go to hell quickly in a firefight.  If the dot fails you ain't got time to figure out why, or how to fix it.  You need to pull the trigger on that guy closing your position.  If your rear sight is up you're going to get the shot off and get a hit.

If he's 300 meters away you've got lots of time.  Heck you can put a new battery in by the time he closes.

It may be quicker to flip a rear sight than change a magazine, but another "trick" is to change magazines when you can vs. when you have to.  There should always be a full mag in the rifle if there's been any sort of lull in the firing.

-- Chuck

The KAC fold down 300 meter iron sight also fits behind the SIR.
Good shootin, Jack