Lower 1/3 Zero and Irons

[punkey71]

Deleted....ASH556 and I had the same traffic.

[Doc Safari]

So with the 1/3 co-witness you still expect to line up the dot with the front sight post?

Then why have a 1/3 co-witness? I thought the purpose of a 1/3 co-witness was so you could use either the RDS or the irons (without having to line up both) if you wished? In other words, it lets you have a fixed rear BUIS that is also out of the way when you're not using it, right?

If you're going to line up all three as in the third pic, then why not have an absolute co-witness?

It's not logical to use a 1/3 co-witness if you are still going to try to line up the dot with the irons all the time.



EDITED TO ADD: Okay, it looks like you can use it either way. The center pic is the one I'd opt for unless the red dot goes down. Then I'd look through it like the third pic.

This is why I gave up and went with a folding rear BUIS. I never could get everything lined up with a 1/3 co-witness.

[ucrt]

.

There was a guy at the range the other night that was saying a RDS was too complicated trying to line the Dot up with the BUIS.
I explained that when the RDS and the BUIS are sighted in, you should just ignore the BUIS and use the RDS. He was using his BUIS and RDS at the same time...whew!!! Just because the RDS and BUIS can Co-Witness, doesn't mean you use them that way all of the time??

The purpose of 1/3 Co-Witness is to have the Dot in the center of the FOV while the BUIS's are down low, not obstructing the majority of the FOV....but ready to go, with a slight head shift, if needed.

If you're not sure your RDS is on target, just look through your BUIS and the Dot should be on the tip of the Front Sight. Then, if all is well, ignore the BUIS and use the Dot, you're gtg.
YMMV

...at least, this is how it works for me.

.

[Failure2Stop]

If you're going to line up all three as in the third pic, then why not have an absolute co-witness?

If you are taking the time to line up all three parts of two sighting systems you are doing it wrong.

[Doc Safari]

If you're not sure your RDS is on target, just look through your BUIS and the Dot should be on the tip of the Front Sight.

This never worked for me. Something is always off-center.

If you are taking the time to line up all three parts of two sighting systems you are doing it wrong.

I'm slowly learning this, hard-headed as I am.

I finally let myself feel guilty about having a cheapo GG&G fold-up BUIS on my carbine, and installed the fixed Daniel Defense 1.5 rear sight instead.

It's going to take some getting used to, but it's not too difficult to use the RDS over the BUIS and then lower my head to sight through the irons if the RDS goes down. The visual clutter isn't as bad as a full co-witness.

Dang, I might actually get used to this tactical shit after all.

[ASH556]

This never worked for me. Something is always off-center.

Probably a head position issue with the irons. That's why the dot is off-center. Either that, or something's not zeroed properly. Have you had quality carbine instruction? As LAV has said, 30 min with a hands-on trainer will explain and fix what would take days on the internet.

[Doc Safari]

Probably a head position issue with the irons. That's why the dot is off-center.

I wear glasses and most people laugh at my head position. I tend to hold my head back and that's just the way it is. That's why I despise a gun like the AK because your face is right at the receiver cover, and why I prefer a tall mount for my T-1. Truth be told, I probably couldn't "unlearn" my stance very easily. After more than 20 years of shooting, though, it's comfortable for me and I have done reasonably well in competitions.

Either that, or something's not zeroed properly. Have you had quality carbine instruction? As LAV has said, 30 min with a hands-on trainer will explain and fix what would take days on the internet.

I had law enforcement range training/time, but nuthin' fancy.

I hit purty near every thing I aim at.

There's a guy at every gun show offering CCW training, and every time I stop and ask about carbine training. All I ever hear is "someday."

[Jaysop]

Hey thanks for the responses guys. I haven't really had a chance to read them all over, my wife's got a stomach bug an I'm chasing a 9 month old around.

I didn't want you guys thinking I didn't appreciate the input.

[ucrt]

This never worked for me. Something is always off-center.
...
...

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There are a lot of variables for everything to line up perfectly; such as: head position, sight cant, old eyes, blah, blah, blah.

When I'm Co-Witnessing, the Dot isn't perfectly top dead centered on the FS post, it is more like on the right side on the top of the post, still very close.

.

[feedramp]

You guys are making this way harder than it needs to be. Check this out:



There's also a whole stickied thread on co-witness in the optics forum, which is where this thread should be to begin with.

The lack of parallax in the T-1 sight makes it possible to accurately view the dot anywhere in the T-1's window.

The lower 1/3 refers to the T-1 being raised to a height such that the irons appear in the lower 1/3 of the T-1's viewing window when centering your eye on the T-1's window.

If you press down into viewing through the irons, and the T-1 and irons are both zeroed for the same distance, you will see the T-1's dot on top of your front sight post. The point is, you can use this version of a co-witnessed sight picture for a quick zero-check on the T-1. However, it is not a replacement for actually zeroing the optic at the desired range.

Oh, duh, I get it now. Of course the mount for the optic is higher.

Thanks for the edumacatin'.