just bought a bushnell trs 25 red dot for my 15-22.will i need a riser to co witness my stock iron sights?if so how high a riser?new to red dots so any help is good to me

I don't own that particular red dot; but you should just be able to mount it and see if it co-witnesses or not....I would think so at least.

Yes, you will need a riser. Most of the micro dot sights made to accommodate an AR platform come with a removable base to install a scope specific riser (see below), but I think that Bushnell low mount is integrated into the scope. If so, you will need a generic 3/4 inch riser.

For those who are thinking about buying a micro dot knock-off you might want to first check to see that it is designed with a removable low base mount and can accept the same risers as the Aimpoint, then you will have a selection of 1/3 lower or absolute co-witness risers, and the low base for pistols or low scope mount rifles.

I have two YHM 1/2" risers on mine to co witness. I call it the nutnfancy setup cause thats where I got the idea but it works really good

Yankee Hill Machine Picatinny-Style Mini Riser Mount 1-1/4" Length Aluminum Matte - MidwayUSA

I have no experience with rails and I am about to purchase a 15-22 MOU. I'm going to probably use the TRS-25 red dot. Cowboy, just to clarify, is that setup I saw on the Nutnfancy video two 1/2 risers mounted? I just want to make sure I buy the correct set-up so I am good to go when it all gets here. Thanks.

I have both the TRS-25 and Primary Arms Micro (essentially same dot optics)...the UTG .83" Mid-high riser will work for absolute co-witness...however, if you decide to go with a 3x magnifier, you will want the 1" riser...either riser can be had for under $8 bucks from Amazon.

There are two kinds of co-witnesses, absolute and 1/3, depending on how YOU the shooter want to see the front and rear sights either one works, here is some pro's & con's for you to decide:

A: Absolute Co-Witnessing: Iron sights are right in the middle of your 30mm tube. Depending on your front sight, fix, or flip up, this setup has the most blockage of your 30mm. Again if RED DOT on, both eyes should be open and this is not a real issue.

B: 1/3 Co-Witnessing: Your Optic's, Red Dot, has at least a .05 riser so your iron sights are at the lowest part of the 30mm tube, (your 6o'clock position of the circle). This offers a clearer view through the optics but still has the ability to use your iron sights if you decide to.

I've got the TRS-25 as well.

0.75" riser = absolute co-witness

0.83" riser = lower 1/3 co-witness


Hope that helps

I have 2 cheap risers in the classified section here if you're interested. Would love to ship them together and then you'd be able to try it with both dimensions...

I spoke with 3RiversPrecision.com about co-witnessing on the Vortex Strikefire with my AR. He said I'd have to get an American Defense QR high mount ($100) if I want the dot clear of the front sight. Does anyone know if this optic will accept a riser?
Thanks

Rideabike06, I have the Vortex Strikefire on my M&P 15/22 with a .05 ARMS riser for 1/3 co-witness. FleaBay has them from $9.10 to $29.00 some are true A.R.M.S. and the lesser are clones, but I have used both clone and ARMS both work. Note on the clones, you may have to file either the top riser or lower mount sometimes, I did on 1 of the clones. I'm at work, I'll post a picture tomorrow of mine with the Vortex & riser.

.05 riser? or 0.5"? typo?

I'm not sure .05" would really be that helpful.

My bad, 0.5, or .387" (22M68) to be more correct per A.R.M.S...fingers are way to slow... Here is the picture:

[IMG][/IMG]

Thanks Ace, turns out Vortex was able to send me an extra high (new item, they said) mount for the Strikefire. Haven't gotten my Magpul BUIS rear yet but looks like it will be a lower third co-witness. Just hoping it won't require a "chin weld" to see through.

You know based on this conversation I might want to try this out some. I have not really decided on what class in 3-gun I am going to shoot but I will need to be able to set up my AR15-22 for practice. PC came with fixed non-foldable metal sights that I just tossed into a box and although I shoot my red dots on risers they are mostly to get better head positioning. I have never considered how they might co-witness. Besides with my eyesight I have an issue with some open sight setups so I usually use FO sights. I do have a set of shooting glasses with a short 18" focus in the right eye that I could use I guess (I use it for shooting a Limited class 1911).

OK. got the goodies. Zeroed the Magpul rear BUIS (American version, you can get the Chinese version for 1/3 the $) and lined the dot up about a quarter inch above the front sight post. If I had it to do over I'd have gotten an AR without the front sight and mounted another flip up on a quad rail. Really like this set up though. Hope the pics come up and this helps somebody.

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You better get that off the couch.

Nice looking Tactical Rifle "rideabike06", you will like this setup if your running and gunning a course with 8" steel plates and/or paper targets. We train a slightly modified "Magpul Dynamic Art of Tactical Carbine" system, but looks very much like Magpuls.. Try this, if is fun, fast and very effective at stopping Zombies and or bad guys.

Magpul Dynamics Art of the Tactical Carbine Volume 1 Live Drill - YouTube

I own a M&P15-22 and bought a Pursuit X1 dot scope. If my calculations are correct, a 1/2 inch riser (which I just ordered today) should work to put the sight on center, in my case. The iron sights are standard non-folding.

First, that is the wrong information. Second, the OP stated he had a TRS-25, so why is everyone posting useless info about their other brands of red dot set ups?......pointless..... I have the TRS - 25 on my 15 - 22. . You need the 1 inch riser for 1/3 co - witness and the . 83 riser for absolute co - witness. I have both risers and recommend going with the . 83 riser for absolute co witness. If you do a 1/3 co - witness the little LED emitter inside the TRS - 25 blocks too much of the sight picture.