I'm new to the ar 15 & before I buy a red dot need some answers. I've read numerous post & even asked Bushnell if the TRS-25 would co-witness with my iron sights. They can't answer but I'll bet someone on this forum can. If this don't work, would appreciate suggestions. Thanks.

The TRS-25 can co-witness with the appropriate riser. The .83" will give you absolute co-witness and the 1" gives you lower 1/3rd.

My Eotech 512 works well with irons; no riser needed.

Get the trs with the included high ar mount and you'll be fine

I have a TRS-25 and Magpul sights on a 10 inch rail front. The Trs-25 co-witnesses with a .075 riser. The total line of sight is 14 inches. The front of the TRS is at approx. 7.5 inches along that line. I'm not an expert at these things, but this sure works well for me.

Thanks for all the response.

Sorry to "threadjack" but what are the advantages behind a lower 1/3 cowitness? When would be be better than an absolute?

Absolute co witness kinda defeats the purpose of using a red dot. To co witness, its generally for if your red dot goes out, you can still use your back up sights. With lower 1/3, you can still use your backup sights through the red dot optics, but you can also use the red dot with the sights up, and the red dot is over the sight line of the sights.

If your backup sights are flip up, both front and rear, I'd go with a lower mount, co-witness. But if you have a A2 frt sight post or a carry handle, I'd go lower 1/3 so the dot clears the sights, otherwise, why have the red dot....

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Rod
M&P 22A, 40c, 15A, 15-22

I'm going to disagree with this. Absolute co witness, in no way defeats the purpose of the red dot, especially if you have a fixed front sight and folding rear.

I have three rifles equipped with red dots currently. Two of them are absolute co-witness and one is lower third. Of the two that are absolute co-witness, one has fixed A2 style front and rear sights, and the other has folders. The third rifle has the fixed A2 front and folding rear.

When shooting both eyes open and focusing down range on the target, I do not even notice the front sight post in the target picture. With the rear sight folded down, cheek weld consistency does not matter... if I can see through the RDS, I can see a dot. With the fixed rear, it is a little more limiting and requires more consistent cheek weld, but it still allows some leeway... you may have to move your head slightly to look either through the rear sight, or to the side or over it.


So, I would agree that it could be a little slower, but it still maintains the advantage of being able to shoot from positions that do not allow perfect sight alignment.

Like most things it depends. If your older and have a lot of time with the AR/M16 platform before optics became the norm then your used to a certain cheekweld/sight picture. Absolute co-witness uses the same cheeckweld as irons.

On the other hands 1/3 co-witness does allow for a less clutered sight picture and better downrange vision, but you have to position your head higher. If you optics go out then you have to adjust your head accordingly

I recommend lower 1/3 with the sport's fixed front sight. If you have a quality optic, you'll be using it nearly 100% of the time. Having the front sight more out of the way for nearly 100% of your shooting makes more sense than being a little more cluttered as the norm.
I do shoot with my irons, rear flipped up, red dot off, and even in that scenario, lower 1/3 lets you see more. The very slight lowering of your face position is quite over stated.