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Posted: 9/20/2002 1:56:55 PM EDT
That is the quesiton......

I guess you can tell that I am ready to spend the bucks on an optical system.

I was just quoted a great price from SWFA for an Aimpont Comp M2 (night vision compatible) and the mount, railgrabber and a few other goodies. And they stayed under my $500 budget.

They assure me that this setup will clear my M4 handguards, but it will place the dot somewhat above the irons.

How important is it to co-witness the irons with the Aimpoint dot?
Link Posted: 9/20/2002 2:25:53 PM EDT
By getting that set up, you will have co-witness. That setup with the rail grabber will put the dot right above the front post, which is perfect co-witness alignment.
Link Posted: 9/20/2002 2:29:02 PM EDT
I thought that particular setup would cause the dot to appear somewhat above the sight plane.

What I would really like is to see the dot sitting right on top of the front sight.

Thanks for the reply, money is burning a hole in my pocket!
Link Posted: 9/20/2002 9:18:39 PM EDT
What Co-witness means is that you are able to see your iron sights through the optic. The set up you are looking at accomplishes this task.

When you use the Aimpoint, you dont want to look through your rear sight, into the aimpoint, at your front sight. Doing this defeats much of the purpose and advantage the Aimpoint offers.

Look just ABOVE you iron sights, past the Aimpoint, at your target. The dot reticle in the Aimpoint will appear on your target. This is what maked the Aimpoint so fast. No sight allignment/sight picture. Just shoulder the rifle, look at your target, and trigger press. VERY fast VERY easy.

Should the aimpont ever go out on you (fat chance!) just lower your head a fraction of an inch, and you can use your irons right through the Aimpoint. Fantastic.
Link Posted: 9/20/2002 10:40:50 PM EDT
I understand that you wouldn't have your BUIS "up" all the time, but if your red dot (Aimpoint, Eotech, etc) and your iron sights are all sighted in for the same POA/POI, and assuming you use the same cheek weld shot to shot all the time, shouldn't the dot be on top of the front sight "if" your were looking through all three at once. I don't understand how the red dot could be above the front sight without changing the POI compared to the sight line of rear to front iron sights. I'm confused.
Link Posted: 9/21/2002 8:55:13 AM EDT
Co-witness threads always seem to lead to some confusion! What everybody needs to understand is there are TWO WAYS to set up Co-witness. You can set it up so the iron sights line up perfectly in the center of the optic OR you can set it up so the iron sights line up in the lower 20%-25% of the optic. I prefer the latter as the iron sights do not "clutter up" the optic's sight picture and with only a slight drop of your head you've achieved Co-witness.
Link Posted: 9/21/2002 5:33:05 PM EDT
A dot scope is always going to co-witness.

If the rifle iron sights and scope are both at a 200 yard (100, 50, 300....) zero then the dot will always appear in front of the top of the front sight post whenever you line up the front and rear sights on target.

The front sight top will not appear behind the dot when using just the dot to aim unless chance has led you to line up the front sight, rear sight and target.
Link Posted: 9/22/2002 10:56:57 PM EDT
So, the second method decribed by AKM with the iron sights alignment positioned in the lower quarter of the red dot sight's field of view will have 2 different points of impact, one for the red dot and one for the aligned iron sights. Yes? Ed
Link Posted: 9/22/2002 11:07:23 PM EDT
No, not at all. So long as your Aimpoint and irons are zeroed at the same range that is. Because as you move your head down to co-witness the irons, the red dot of the Aimpoint will also move to the lower portion of the glass.
Link Posted: 9/22/2002 11:12:05 PM EDT
Are you going to use the stock front sight housing (the triangular one)?

If you are going to co-witness with the stock front sight, then you HAVE to raise the dot sight a bit. Otherwise, if you look straight through the tube, the front sight will obscure your sight picture.

On the other hand, if you use a "flip up" front and rear, you could mount the optic somewhat lower.

I have use an Aimpoint Comp M2 with the ARMS detachable mount w/spacer, backed up with an ARMS #40 flip up. I sighted the rear sight in for 200 yards, mounted the optic, then adjusted it so that the dot sits just on top of the front sight when I look through the the rear.

It's an excellent system.

Link Posted: 9/23/2002 5:18:38 AM EDT
[Last Edit: 9/23/2002 6:34:21 AM EDT by AKM]
Sorry if I added to the confusion with my first post. The Aimpoint is PARALLAX free, hence it matters not if the dot is centered in the "tube". The dot is your point of impact (once sighted in) no matter where it may end up within the tube.
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