PDA

View Full Version : Optics and the FSB?


Locutus
02-10-12, 17:14
I've read a lot here, including the stickeys, searched a lot here, but I have a couple of questions that just have not been answered that I've been able to find. Here's my second one...

I have a POF with no FSB and a rail and I've equipped it with an EOTech and Magpul Gen II BUIS. It works quite well with no FSB in the way and I can sight right through the EOTech if the batteries ever die or it craps out. In fact, the red dot lines right up with my BUIS and that leads me to my question:

I now have a BCM upper coming with a FSB and I intend to keep this one simple. However, if I did choose later to add an optic, I assume that to not be obstructed my the FSB, I'll need to elevate it at least a little. However, if I elevate it completely above the sight plane of the iron sights, it would be way above the normal cheekweld, so do people get high stock attachments, or can the optic be elevated enough to have the dot above the FSB, while still being low enough overall to sight through it with irons?
Hmac
02-10-12, 17:30
You want to be able to use your irons through the optic, but no need to go to any extra trouble to get them out of the way. I mount mine so that the irons co-witness in the lower third, but that's a preference thing. Many people prefer that they co-witness in the center. You won't notice the FSB in the picture after a few shots.
Locutus
02-10-12, 17:38
You want to be able to use your irons through the optic, but no need to go to any extra trouble to get them out of the way. I mount mine so that the irons co-witness in the lower third, but that's a preference thing. Many people prefer that they co-witness in the center. You won't notice the FSB in the picture after a few shots.

So when you say "co-witness" you only mean that you can see your irons through the optic in the lower third, and not that the red dot is actually in line with the irons as it is on my POF, correct? If so, that sounds perfect.

I've seen very nice comments about the Aimpoint Pro and it costs just a tiny bit more than my EOTech did, so if I could mount it as you describe (or at least as I understand it), then that would really be nice. I plan to shoot the shit out of my BCM for awhile before I make any more decisions, but your help is appreciated! :D
Locutus
02-10-12, 19:25
So when you say "co-witness" you only mean that you can see your irons through the optic in the lower third, and not that the red dot is actually in line with the irons as it is on my POF, correct?


Since the Moderator (Failure2Stop?) moved this to Tactical Gear/Optical Mounts, I see there are stickys I wasn't aware of. I've already learned a good bit more... Thanks.
Hmac
02-10-12, 20:30
You want to be able to sight your irons through your optic, the theory being that if your optic goes down, all you have to do is flip up your rear sight and the irons are now usable without having to remove the optic. That's co-witnessing. Your choices typically are absolute co-witness, with the sights lining up in the middle of your optic, or lower-third co-witness where they line up in the lower third. In the case of the Aimpoint PRO with the stock QRP mount, it will co-witness somewhere in the lower 1/2. Works great, and you won't really notice the FSB in the picture.

In most situations, whichever co-witnessing scheme you choose, if you sight the front/rear iron sights with the red dot on, the dot will sit right on the tip of your front sight post.

Eotechs have some advantages and disadvantages, as do Aimpoints. The Aimpoint PRO is indeed a nice functional optic and very cost-efficient.
Kokopelli
02-10-12, 20:36
I have a couple of pics.. In both cases (different carbines) the irons were zeroed first and then the optic.. Ron

This one is the Nikon M223 at 1X..

http://i267.photobucket.com/albums/ii309/Hohopelli/DSC07940.jpg

This one is the Burris red dot looking through the 50m aperture.. Not a very good pic, but you can see the dot is smack on the front post..

http://i267.photobucket.com/albums/ii309/Hohopelli/DSC08011.jpg
boomhower
02-10-12, 20:52
Aimpoint pro will treat you will. I've had mine for a year and love. I swapped out the mount for an ADM lower third with QD. It's a great setup. I'm a huge fan of fixed sites for defense or duty weapons. After you use it for a while you don't even notice them. If crap goes south I don't want to be flipping switches to get a site up.


Sent from my iPhone 4S using Tapatalk