Maximum effective forward mount of a RDS

[MonkeyHEMI]

I know the issues with handguards not being completely stable and potentially causing loss of zero. I'm not worried about that and am only looking for input on the actual usability of a RDS when it's pushed forward more.

How far can one actually place their eye from a RDS and still see a usable dot?

Does distortion of any sort through the lens become a problem?

I'm thinking of installing one at the end of a 12" handguard.

So anyone have experience with this? Maybe know of one brand that would allow more distance over another?

[militarymoron]

why would you want to mount one so far forward?

[lethal dose]

I know you don't want to hear it, but there is no way you could justify this other then having and a1/a2 upper. In that case, I'd consider a gooseneck (personally, I'd stick to irons with a fixed carry handle). To answer your question, I guess you could put it out as far as you wanted as long as YOUR eyes could see it. All this to say: in no way, do I recommend this.

[MonkeyHEMI]

The intent is to speed up targeting. I have a 3x fixed primary and will be experimenting with a RDS in the far forward 9 o'clock position for rapid transitions between sights. The idea with placing it as far down the barrel as possible is to keep it from interfering with field view. I've used guns with 1 o' irons and while rotating a few degrees was adequate I want to see if my eyes can adapt to this style and have a more rapid/fluid transitions between sights.

Maybe someone could provide input on which sights have the widest eye opening, or rather which may be easier to view from way back. I'm looking at the RMR because of it's selection of large MOA dots and it seems like it has a fairly large viewing area.

[lethal dose]

Viewing area does not exist in a non powered RDS. It's a figment of your imagination. Also, putting the RDS farther forward will actually slow target acquisition down.

[misanthropist]

A number of years ago I had an M14 with a scout mount with a red dot on it. That must have been twenty inches from my eye.

At the time it seemed more reasonable than it does now. Lots of guys ran forward RDS optics back then. Also .308 was $300/1000...so yeah, that was a while ago.

Anyway one thing I'll say for that approach...by the time you're looking through the optic, the gun is sufficiently aligned with the target that finding the dot sure isn't a problem.

I never had any trouble with the dot being out that far as far as seeing it goes, but I was fairly young and had very sharp vision so I'm not sure what it would be like for most people.

Anyway I wouldn't do it today, but it can be done. I would be curious to hear the reason for wanting to do it this way, though.

[MonkeyHEMI]

Viewing area does not exist in a non powered RDS. It's a figment of your imagination.
Maybe you misunderstood. Viewing area 100% exists. It's the area viewable from the opening for the eye (outlet). Even on the RMR the unit has a certain amount of lens area that can be measured exactly by it's width

Also, putting the RDS farther forward will actually slow target acquisition down.
That sounds like a pretty relative statement.

A number of years ago I had an M14 with a scout mount with a red dot on it. That must have been twenty inches from my eye.

At the time it seemed more reasonable than it does now. Lots of guys ran forward RDS optics back then. Also .308 was $300/1000...so yeah, that was a while ago.

Anyway one thing I'll say for that approach...by the time you're looking through the optic, the gun is sufficiently aligned with the target that finding the dot sure isn't a problem.

I never had any trouble with the dot being out that far as far as seeing it goes, but I was fairly young and had very sharp vision so I'm not sure what it would be like for most people.

Anyway I wouldn't do it today, but it can be done. I would be curious to hear the reason for wanting to do it this way, though.

I'm pretty young still and my eyes are pretty well trained

Glad to hear its a feasible idea. I picture it being a lot like a shotgun sight with slightly increased aiming capabilities. Something my eyes should be able to train to use by just switching from right to left.

[militarymoron]

my .02. i wouldn't mount it in the 9 o'clock position. i'd get an offset mount that puts it just to one side of your primary (11 or 1 o'clock), so you only have to rotate the rifle 10 degrees or so. if it's in the 9 o'clock position, how are you going to sight through it?
if you're looking for more rapid/fluid transition between sights, putting the secondary further away where it requires you to rotate the gun more isn't going to do it.
are you shooting right handed or left handed? if the RDS is at 9 o'clock, and you're right handed, where's the support hand? will it get in the way of the RDS? what's going to happen to cheek weld and stock position in the shoulder when rotating the rifle that much?
those are larger questions to me than whether you can use an RDS that far away from the eye. an RDS will work that far away - it's the same as mounting them on handgun slides, and those are at arm's length.

[lethal dose]

Explain what you mean by viewing area. You calling it the same thing as field of view?

[MonkeyHEMI]

Mil
I appreciate the input but I'm not asking for input on the concept. What works best for me may never work for anyone else. I'm asking for specific technical info and the thread was created with the idea of gathering info that concerns me, not you or others.

Not at all trying to be a jerk.. Just making sure my thread stays on track so I can collect relevant info.

Lethal
I would define a units "field of view" as it's maximum view of the field. Field of view also implies that it's the devices view of something.
That units viewable area would be the area on the unit occupied by a viewable lens which allows viewing through the device. Opposite of "field of view" the term "viewable area" implies something to be viewed on the device.