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Page AR-15 » Optics, Mounts, and Sights
AR Sponsor: bravocompany
Posted: 9/28/2011 6:51:52 PM EDT
This could be a very stupid question, but I have noticed in most pictures, people have their red dots placed at the furthest possible point on their upper receiver. Is there a reason for this other than the potential to add a magnifier behind the optic itself?
Link Posted: 9/28/2011 6:58:14 PM EDT
[#1]
good question. Lacking a magnifier I like to put the red dot as close to my eye as possible to increase field of view.
Link Posted: 9/28/2011 6:59:04 PM EDT
[#2]
Quoted:
good question. Lacking a magnifier I like to put the red dot as close to my eye as possible to increase field of view.


If you're shooting properly (both eyes open) the FOV through the optic itself is irrelevant.
Link Posted: 9/28/2011 6:59:13 PM EDT
[#3]




This is not a stupid question. The greater the distance between the front and rear positions of any sight, the longer the sight baseline length and the higher the potential accuracy that can be obtained from the sight.
By putting the red dot system as far forward as possible, the greater the baseline length between the front sight (red dot) and the rear sight (your eye). The other key when using your eye as the rear sight is to have a repeatable cheek weld on the stock.



ETA: Fire up your red dot. Cover the front with a lens cap (cardboard will do to). Now, with both eyes open, look out at something as far away as possible.  You should see the red dot superimposed into the overall picture your mind creates by joining together what both eyes see. This is the Binding Aiming Concept and it can be very useful.

Link Posted: 9/28/2011 7:07:08 PM EDT
[#4]
Did you try the Optics forum?
Link Posted: 9/28/2011 7:28:30 PM EDT
[#5]
Topic Moved
Link Posted: 9/28/2011 10:46:52 PM EDT
[#6]
The dot focus is superimposed on the target regardless of the position of the sight.
Size of the dot looks the same regardless of position.
Some believe it is faster if the red dot sope is further out.  Probably is if you started out using red dot on a pistol in competition.
Downside is that it adds weight to put the sight on the end of the barrel.
If using a absolute cowitness red dot sight nearer the rear of the rail and the red dot is not on it will work better as a temporary rear aperature as apposed to being all the way forward on a forearm rail.
Link Posted: 9/29/2011 3:09:45 AM EDT
[#8]
Thanks for the quick feedback. I was finding it hard to swallow that the distance from the eye to the optic made a crucial, if any, impact on accuracy (sorry to disregard the advice of the poster who made this comment, but thanks none the less). Just thinking about it logically, if this were the case, we would regard the scout set up on rifles as being inherently more accurate than their traditionally mounted cousins, which I do not think is the case.

I can also see validity to the idea that the increased sight picture is negligible with regards to FOV because both eyes should technically be open, which would eliminate this argument... Damn these conundrums! lol. Regardless, thanks for the posts, I'm still very interested in people's opinions and any discussion that might ensue.
Link Posted: 9/29/2011 11:31:01 AM EDT
[#9]



Quoted:


Thanks for the quick feedback. I was finding it hard to swallow that the distance from the eye to the optic made a crucial, if any, impact on accuracy (sorry to disregard the advice of the poster who made this comment, but thanks none the less). Just thinking about it logically, if this were the case, we would regard the scout set up on rifles as being inherently more accurate than their traditionally mounted cousins, which I do not think is the case.



I can also see validity to the idea that the increased sight picture is negligible with regards to FOV because both eyes should technically be open, which would eliminate this argument... Damn these conundrums! lol. Regardless, thanks for the posts, I'm still very interested in people's opinions and any discussion that might ensue.


I'd suggest shooting at a 100 yard target with the sight as far forward as possible and as far back as possible. Compare five 10 shot groups done from each position and see which one gives you better groups.



I am old school - shoot the SOB while he is as far away as possible and use a double stack 45 for CQB.



 
Link Posted: 9/29/2011 12:51:27 PM EDT
[#10]
Quoted:
Size of the dot looks the same regardless of position.
That's sort of true in the case of the EO Tech with the 65 MOA ring. While the ring size is the same relative size regardless of where the optic is placed, the further away from your eye it is, the more of the "viewport" the reticle takes up to the point where you can't move your head that much without losing part of the ring.

This isn't an issue with the dot itself because it's only 1 MOA. The same is true with any single dot red dot.

Link Posted: 9/29/2011 1:19:44 PM EDT
[#11]
sort of threadjack, but say you have a collapsible stock in the most compact position (and nose to charging handle) and zero in your red dot at 50 yds.  if you move the stock to the most extended position (nose now maybe several inches away from the charging handle) will a red dot still hold zero at 50 yds?
Link Posted: 9/29/2011 1:46:36 PM EDT
[#12]
Yes 50 yard zero is 50 yd. zero. The dot doesn't move.
Link Posted: 9/29/2011 1:51:59 PM EDT
[#13]
so distance from eye to red dot has no effect on where the POI will be?  Looks like I need to tighten up my mount and re loctite :D
Link Posted: 9/29/2011 3:49:01 PM EDT
[#14]
Quoted:
so distance from eye to red dot has no effect on where the POI will be?  Looks like I need to tighten up my mount and re loctite :D


Assuming your rail is straight...
Link Posted: 9/30/2011 1:44:43 AM EDT
[#15]
Quoted:
Quoted:
good question. Lacking a magnifier I like to put the red dot as close to my eye as possible to increase field of view.


If you're shooting properly (both eyes open) the FOV through the optic itself is irrelevant.


Not quite true as the closer the optic is to your eye the less the optic itself obscures your view. When the optic is far from your eyes your target can be obscured by the knobs and other parts of the optic itself.
Pat
Link Posted: 9/30/2011 6:53:21 AM EDT
[#16]
I keep my eyes open and can't see the sight at all.  But my experience has been with smaller RDSs like the old Armson OEG and the Hensoldt RSA.

Edit: Never mind...  I just realized you were pointing out that this doesn't work if the sight is too far from your eyes.  That is very true.
Link Posted: 9/30/2011 7:01:12 AM EDT
[#17]
I haven't found it to be critical where it is placed on the rail. I personally prefer to put forward. Everything becomes second nature with repeated use (call it training, whatever).

I like this advice:

I'd suggest shooting at a 100 yard target with the sight as far forward as possible and as far back as possible. Compare five 10 shot groups done from each position and see which one gives you better groups.


I can already predict which group would be better Even if you do this with a rest or bags to support the hand guard you might still see a difference in the 2 groups.

Over the past several years I had to rethink a lot about how I used to do things. I came to realize that I may have 'liked' or 'preferred' how I did something, but I found that it was just not anywhere near as effective or efficient as another way. Give different things a try and see what's more effective.
Link Posted: 9/30/2011 10:43:09 AM EDT
[#18]



Quoted:




This is not a stupid question. The greater the distance between the front and rear positions of any sight, the longer the sight baseline length and the higher the potential accuracy that can be obtained from the sight.



By putting the red dot system as far forward as possible, the greater the baseline length between the front sight (red dot) and the rear sight (your eye). The other key when using your eye as the rear sight is to have a repeatable cheek weld on the stock.



ETA: Fire up your red dot. Cover the front with a lens cap (cardboard will do to). Now, with both eyes open, look out at something as far away as possible.  You should see the red dot superimposed into the overall picture your mind creates by joining together what both eyes see. This is the Binding Aiming Concept and it can be very useful.



Doesn't this only hold good for fixed sight references at each end of the gun, ie a foresight and a rearsight? If the dot is as far forward as possible, any movement the further out you go will be greater as the lever arm/and radius from your shoulder is greater, so it would be better to have your dot as far back as possible to minimise the movement. I don't understand how the eye can be a rearsight, if you can't guarantee it's position every time, especially in the situation a dot is intended for, ie cqb & fire and movement?

 
Link Posted: 9/30/2011 7:17:50 PM EDT
[#19]
Quoted:

Quoted:

This is not a stupid question. The greater the distance between the front and rear positions of any sight, the longer the sight baseline length and the higher the potential accuracy that can be obtained from the sight.

By putting the red dot system as far forward as possible, the greater the baseline length between the front sight (red dot) and the rear sight (your eye). The other key when using your eye as the rear sight is to have a repeatable cheek weld on the stock.

ETA: Fire up your red dot. Cover the front with a lens cap (cardboard will do to). Now, with both eyes open, look out at something as far away as possible.  You should see the red dot superimposed into the overall picture your mind creates by joining together what both eyes see. This is the Binding Aiming Concept and it can be very useful.

Doesn't this only hold good for fixed sight references at each end of the gun, ie a foresight and a rearsight? If the dot is as far forward as possible, any movement the further out you go will be greater as the lever arm/and radius from your shoulder is greater, so it would be better to have your dot as far back as possible to minimise the movement. I don't understand how the eye can be a rearsight, if you can't guarantee it's position every time, especially in the situation a dot is intended for, ie cqb & fire and movement?  


Ya, there is no sight radius for a RDS its only for iron sight type optics and it's arguable that sight radius has any affect at all.  

Not necessarily, if you are a tactical shooter where speed is integral, i.e. two way range, reticle speed may be important to you.  Speed + Accuracy = win.  If you only shoot from a bench, however, speed probably isn't that important to you.
Link Posted: 9/30/2011 7:56:49 PM EDT
[#20]


Some thoughts:





  • Regardless of near or far placement of a RDS on your rail, your speed for taking a shot is the same because you have to have the entire rifle barrel correctly aligned before you can take a shot.

  • Regardless of any white paper written by any trainer, sniper or other cited authority - physics is a science and non-belief in sight radius is irrelevant - especially when you don't know that you are using it

  • If you want to find out what works best, look at how the largest possible group placed in life or death scenarios uses a tool or document your own efforts using the tool under multiple configurations to determine what gives you the best results.



If all else fails, go to the people who make the tool and ask them how they designed it to be used or find a detailed explanation of the same. It doesn't matter what your buddy at the range told you; he didn't design the tool.



http://ultimak.com/UnderstandingE-sights.htm



Best link I could find that gives an overview of the different options.
Link Posted: 9/30/2011 10:28:13 PM EDT
[#21]
Quoted:
  • Regardless of near or far placement of a RDS on your rail, your speed for taking a shot is the same because you have to have the entire rifle barrel correctly aligned before you can take a shot.

Partially agree, I would argue that I personally shoot faster with an aimpoint mounted further forward (not true for everyone) and thus taking up less of my field of view, but I agree that the optic would sit along the same point of aim regardless of position and thusly not increase speed form that perspective. I was merely trying to say that speed and accuracy are both necessary and one should not be overlooked to favor the other completely

  • Regardless of any white paper written by any trainer, sniper or other cited authority - physics is a science and non-belief in sight radius is irrelevant - especially when you don't know that you are using it

  • Sight radius is not physics actually and it is by definition unrelated to use of a RDS. It is a theory that basically says that the longer the distance between sight posts, the easier it is to see misalignment of iron sights and in turn allowing for more accurate shots.  There is no alignment for a RDS so no sight radius. And as I said it can be argued that regardless of sight radius a good shooter can still make just as good a shot.

  • If you want to find out what works best document your own efforts using the tool under multiple configurations to determine what gives you the best results.

  • agree

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