Looking at the Burris FastFireIII to mount on the Picatinny rail of my M&P Sport. I want it to co exist with the TOP of the front fixed sight (easier to sight in) and I want it to mount in front of my MBUS flip up sight that came with the Sport. Will I need (2) 1/2 inch mounts to co exist with the front sight? Probably need to remove rear sight for sight pattern...I realize many will recommend Eotech or Aimpoint but I need to know Red Dot is the way I want to go...
Looking to get a Red Dot to co exist with fixed A2 front sight
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ChattanoogaPhil
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I've got a FF3 on a Ruger pistol. I don't think much of the FF3 for an AR platform anyway... but Burris does make a sight specific AR riser/mount for it (link below). The FF3 has a bit of magnification distortion due to the curvature of the glass. It's distracting enough on my Ruger but never tried it on an AR for cowitness. I'd look elsewhere... Primary Arms, Busnell and Vortex all make sub $200 true 1x red dots that are better suited for an AR platform and cowitness IMO.
Now... to answer your original question. Using the FF3 picatinny mount, the center of the glass is about .75in above the rail on my Ruger. A generic .75in riser will work. A .5in will be too low and 1in will be too tall.
AR-F3 Sight - rifle scopes, handgun scopes, hunting scopes by Burris Optics
Now... to answer your original question. Using the FF3 picatinny mount, the center of the glass is about .75in above the rail on my Ruger. A generic .75in riser will work. A .5in will be too low and 1in will be too tall.
AR-F3 Sight - rifle scopes, handgun scopes, hunting scopes by Burris Optics
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MichiganScott
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That's known as co-witness. Coexist is defined as living peaceably side side.
That being said, you will most likely need risers much higher than 1/2". The Burris Fastfire are really designed as primary sights on pistols or secondary sights on AR's with scopes.
That being said, you will most likely need risers much higher than 1/2". The Burris Fastfire are really designed as primary sights on pistols or secondary sights on AR's with scopes.
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While we are on the subject....
I'm looking at an AimPoint Pro Patrol. The add states "...indexes the sight at the optimal height for co-witness with the standard iron sights on AR15/M16/M4 carbine style weapons."
Sooooo, I'm assuming it will co-witness with my standard Sport front sight.
Yes, no? Anyone with experience with this AimPoint?
I'm looking at an AimPoint Pro Patrol. The add states "...indexes the sight at the optimal height for co-witness with the standard iron sights on AR15/M16/M4 carbine style weapons."
Sooooo, I'm assuming it will co-witness with my standard Sport front sight.
Yes, no? Anyone with experience with this AimPoint?
gunny4053
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In my opinion, the Fastfire III would not be my first choice for an AR optic. Red dots are certainly great options on AR's, but there are better, more durable, less expensive sights to be found. Primary Arms micro dot or 30mm red dot would be, IMHO, a better choice. The 30mm red dot can be had for about $90, including mount and shipping. I bought mine, not just because of the price, but because battery life is listed as 800 to 1000+ hours on a single battery. The other nice thing about ordering from them, they provide the mount options for the sight you select. For example, lower 1/3 co-witness, absolute co-witness, straight, cantilever,inexpensive, or high end mounts, anywhere from $10 to $100+. You won't have to worry about standoffs', because the provided mounts are made specifically for your application. Something to consider. 
Mine is set up for absolute co-witness.
Good luck, whatever your choice may be.
Good Luck and good shooting.
Mine is set up for absolute co-witness.
Good luck, whatever your choice may be.
Good Luck and good shooting.
gunny4053
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Rland1972
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In my opinion, the Fastfire III would not be my first choice for an AR optic. Red dots are certainly great options on AR's, but there are better, more durable, less expensive sights to be found. Primary Arms micro dot or 30mm red dot would be, IMHO, a better choice. The 30mm red dot can be had for about $90, including mount and shipping. I bought mine, not just because of the price, but because battery life is listed as 800 to 1000+ hours on a single battery. The other nice thing about ordering from them, they provide the mount options for the sight you select. For example, lower 1/3 co-witness, absolute co-witness, straight, cantilever,inexpensive, or high end mounts, anywhere from $10 to $100+. You won't have to worry about standoffs', because the provided mounts are made specifically for your application. Something to consider.
Mine is set up for absolute co-witness.
Good luck, whatever your choice may be.
Good Luck and good shooting.
That looks so sexy. Mine comes in on Monday. Good prices for sure at primary arms.
gunny4053
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saltair,
First let me apologize. I made suggestions but didn't really address your question. I believe Chattanoogaphil hit the nail on the head, a .75" standoff should do fine, if you decide to go with the FF3. Beyond that, I still believe there are better, less expensive choices for you to consider.
Good Luck and good shooting.
Rland1972, did you get you sight today? If so, I think you're going to be very pleased.
First let me apologize. I made suggestions but didn't really address your question. I believe Chattanoogaphil hit the nail on the head, a .75" standoff should do fine, if you decide to go with the FF3. Beyond that, I still believe there are better, less expensive choices for you to consider.
Good Luck and good shooting.
Rland1972, did you get you sight today? If so, I think you're going to be very pleased.
Thanks all, for your recommendations. I went with and ordered the Primary Arms 3 MOA Gen II red dot with Kill Flash and absolute co-witness. Maybe I should have gone with the lower 1/3 co-witness but this is my first red dot and for under $100 I'm sure I can make due and learn from the experience. I did try the NcSTAR at my LGS but it had a starburst above the red dot so I gave it back. Nick at Primary Arms was very helpful. I put PA on my bookmarks.
ChattanoogaPhil
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The guys at Primary Arms are first class. I think you made a better choice than the FF3. The kill flash will end up in the AR parts box.
The guys at Primary Arms are first class. I think you made a better choice than the FF3. The kill flash will end up in the AR parts box.
Along with my holsters, springs, triggers and buffers...
Rastoff
US Veteran
But they look so cool! Isn't that the point?The kill flash will end up in the AR parts box.
Rland1972
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Rland1972, did you get you sight today? If so, I think you're going to be very pleased.
Yes it came in. I'm very happy with it.
Thanks for the help.
gunny4053
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Lookin' good.
ChattanoogaPhil
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Rland1972,
You might consider moving it forward on the reciever.
You might consider moving it forward on the reciever.
Rland1972
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Would you please explain why? I'm new to the AR and red dot world and have no idea what would be the difference/benefit. Thank you.
ChattanoogaPhil
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For starters, you don't need your rear sight up against the optic when flipped up. If it's further away you can see over the sight when it's flipped up and using the red dot. For that matter, flip or fixed rear sights really don't make a lot of difference with a red dot is mounted forward., but when the rear sight is up and pushed up against the optic it's blocking the window period. More importantly, when the sight is further forward aiming is more repeatable. Try it forward and then to the rear and see how you like it best.
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Rland1972
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Thank you. I just moved it forward and like it much better. The stock front sight is much less visible. Is there any technic of any kind to adjusting where to mount the sight on the gun or is it more of what feels comfortable. It's all the way toward and looks a little odd to me.
ChattanoogaPhil
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No, there is no red dot position law.
Just keep it on the receiver.
Try it in different positions and see how you shoot. Some guys who never learn to shoot with both eyes open do better with the red dot moved rearward because they peer through the red dot like a kid with an empty toilet paper tube and suffer limited field of view.
Just keep it on the receiver.
Try it in different positions and see how you shoot. Some guys who never learn to shoot with both eyes open do better with the red dot moved rearward because they peer through the red dot like a kid with an empty toilet paper tube and suffer limited field of view.
Rland1972
Member
Okay thanks. I haven't been able to shoot yet but I have been aiming at things in the house (unloaded and double checked of course). It does take some getting use to and I naturally close one eye at first but I'm coming along well and it's getting easy to sight in with both eyes now.
Again Thank you.
Again Thank you.
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