reflex sight vs. what sight radius?

[bluejeans]

i am now starting a project i have been planning and gearing up for for some time... making my 327pd into a switch barrel gun to give me various options of barrel lengths so i can use my favorite gun for more purposes.

the purpose of this inquiry is to decided what sight options to place on the various barrel lengths. offhand i'm thinking open sights <4" then a reflex sight and the longest (~7-8") railed for a scope. ---- but i have little experience with red dot sights so:

1. at what sight radius are open sights comparable to a reflex sight in accuracy? (shorter barrel/sight radius = worse accuracy for open sights but a reflex sight remains constant... )

2. what is your best distance for using a reflex sight? (ability to bring on target up close, MOA dot size limiting your distance i'd imagine...)

i hope those questions made sense. looking foreword to learning from others' experience.

 

[LoneGoose]

In my very limited experience (and also limited by my shooting skills) the red dot sight works well up to 25 yards for silhouettes. Farther than that and the dot gets in the way for me. For bullseye targets, I use iron sights. With irons, I can hit a 12" gong at 100 yards about 20% of the time. With my red dot, I can't see the gong. Good luck, good shooting.

 

[RON in PA]

The distance a red dot sight is usable is a function of dot size. For use at longer distance small dots such as 3 MOA are recommended while 8 MOA is often recommended for pistol use at close range.

 

[bluejeans]

ok that helps with the question of distance. how about red dot in relation to sight radius comparisons?

thanks guys.

 

[BCRider]

ok that helps with the question of distance. how about red dot in relation to sight radius comparisons?

That's going to be tougher to nail down.

The error you might have with a red dot will be based on the size of the dot in MOA in relation to the size of the black or other colour center area of your target. The error in iron sights is going to be based on the base line length and any amount of side to side gap variation you are not able to see and compensate for.

Of course this all supposes you are performing slow paced bullseye shooting and not shooting while on a timer.

All in all having tried both for slow paced shooting I'll take the plain sights any day over a red dot. The handgun size dots are simply too large so they can be seen rapidly in a speed shooting situation to use for slow deliberate bullseye shooting.

But if the game is speed then the red dot is king since you have one less part to line up when obtaining your sight picture.

This would hold true regardless of barrel length.

Since you don't say what style of shooting you'll be doing I'll just end my comments with the idea that you've got your sights preference backwards.

The short sight baseline of the under 4" barrels suggests that a red dot is the way to go. I see shorter barrel options as being more about closer in speed based shooting than longer barrels which are more for bullseye games or handgun hunting or just longer distance target plinking. Either way I'd want plain sights or maybe a handgun scope over a red dot.

The longer sight baseline length of the long barrel would be better with the iron sights just because for the longer distance you won't be masking the target with an oversize red dot and the longer baseline length makes small errors in the sight picture easier to see. Or another way of looking at it is that any errors in front blade centering you can't see are going to produce smaller errors.

Now all red dots are not created equal. I've seen a couple that have a sighting pip that is selectable between a dot, a + and a small circle. The + and circle might allow you to see the small center spots of a more distant target and center the + over it with less masking. Or for more demanding shots to center the targets center area within the glowing circle of the sight. A red dot style sight of this sort might end up being better for long range than a plain dot. A lot would depend on how the alternate sight pips key in visually with the target.

 

[Skribs]

I'm going to agree with the subjective part of what BCRider said - you get the most out of going with a red dot over open sights in the shortest barrels. It's like you said, the shorter the barrel, the shorter the sight radius, and the worse the irons will be. That's when you will get the most benefit out of upgrading to a red dot.

I think a longer barrel will benefit you the most going to a scope, because you'll want both for accurate shooting at range.

Open sights are nice because it gives you a lower profile with the weapon, it's easier to store the weapon, (compared with some red dot sights) there is no batteries, and I do think revolvers look better when it's just the gun. But if I wanted it for targets, I wouldn't have irons.

 

[chicharrones]

Irons are great until your eyes can't see them anymore. In that case, sight radius doesn't mean much anymore. Like my case in particular.

For red dots used for accuracy, I just use a 6 o'clock hold. That way the dot doesn't obscure the target.

 

[chicharrones]

Now all red dots are not created equal. I've seen a couple that have a sighting pip that is selectable between a dot, a + and a small circle. The + and circle might allow you to see the small center spots of a more distant target and center the + over it with less masking.

Yeah, those red dot sights with a + inside a circle look good in catalogs. In use the circle is so tightly positioned around the + that the whole thing messes with my view of the target. I sort of like the + by itself, but I've really just come back to simple dots because the + still covers tiny targets too much. In my experience, a lit + in a red dot is not as fine as a cross hair in a scope. (Illuminated scopes may be different.)

Now, the EOTech size of circle is completely different. It is much larger and doesn't impede using the center dot like some of the others do.

 

[bearcreek]

In my very limited experience (and also limited by my shooting skills) the red dot sight works well up to 25 yards for silhouettes. Farther than that and the dot gets in the way for me. For bullseye targets, I use iron sights. With irons, I can hit a 12" gong at 100 yards about 20% of the time. With my red dot, I can't see the gong. Good luck, good shooting.

In a class I took earlier this year the instructor had almost everyone in the class making 1st or 2nd round hits at 650 yards on a torso size silhouettes with whatever optic they came with. Most had red dots of some sort. I had an Aimpoint Comp M3 on a 14.5 in barrel AR with non free float handguard. At that distance you're aiming 4-5 ft over the top of the target. I never would have thought I could do that before that class. It's mostly about the technique.

 

[MachIVshooter]

That's going to be tougher to nail down.

The error you might have with a red dot will be based on the size of the dot in MOA in relation to the size of the black or other colour center area of your target. The error in iron sights is going to be based on the base line length and any amount of side to side gap variation you are not able to see and compensate for.

This. You'd have to compare specific sights. Precision target irons will eclipse the potential of really any RDS, but the shooter has to know how to use them. Conversely, a small MOA dot sight with a crisp reticle is probably more precise than most standard handgun sights.

The reason to select an RDS, however, really has nothing to do with precision; it's about speed, and a single plane sight with an illuminated dot is much faster than aligning irons. It also allows the shooter to superimpose the dot on a target that is in focus, rather than a crisp front sight with fuzzy rear sight and target.

 

[BCRider]

I'd never thought about using the dot in a 6 o'clock hold. That's a good one! It does put some importance on the size of the target and the distance since 6 o'clock holds are highly dependent on the same distance to bull size geometry. But for those cases it could really aid the accuracy and cures the issue of the dot being bigger than the center dark area.

Another factor to consider for us old farts with "oldguyeyetis" is that a red dot sight optically projects the focus of the dot out at infinity. In every day terms this means that we can wear our glasses which allow us to see the distant target the most clearly and that the dot will also be clear. Optically our eye sees both the target and dot at near enough to "infinity" for focusing that they'll both be sharp. No putzing around with sharp front blade and fuzzy target and rear notch issues and half power readers and other tricks.

So in a way red dots are old guy vision friendly where regular iron sights on handguns are not.

Another conundrum is that the longer the sight baseline length on the plain sights the easier it can be to see small errors. But with that the rear notch can tend to be more fuzzy than it would be if the rear and front sights were closer together. And that higher level of rear notch fuzziness can end up hurting the ability to see the small errors that we're looking for.

So what would be an "ideal" distance between the sights? That depends on the shooter's vision and how bright out it is.

A trick that can help on bright sunny days is to not wear sunglasses. Or at least pick glasses with greater light transfer. By letting more light into our eyes our iris closes down a little more and we will have a greater depth of field. So fuzzy old guy eyes sharpen up by around "10 years".

For indoor ranges the more light on the target area the better. But if it's dark all around the firing line we still will have problems. At that point is where a stick on aperture on the shooting glasses comes in handy.

 

[Pete D.]

sights

A trick that can help on bright sunny days is to not wear sunglasses. Or at least pick glasses with greater light transfer. By letting more light into our eyes our iris closes down a little more and we will have a greater depth of field. So fuzzy old guy eyes sharpen up by around "10 years".

a very useful piece of information. Well said. Thanks.

Iron sights and red dots are not really comparable in terms of sight radius. Iron sights are a three element system....the rear sight, the front sight and the target. Regardless of sight radius, this system is compromised by the limitations of the human eye. To be effective, a shooter has to align all three elements, each of which is a different distance from the eye. Since it is impossible for the human eye to focus on two different objects at different distances at the same time, that means that two of the three elements are going to be out of focus.
Red Dot sights - a two element system (the dot and the target) , tubular or reflex, eliminate the out of focus element by putting the aiming dot at infinite focus - essentially on the same plane as the target. Both elements are in focus
The limiting factor is the size of the dot (which can be had all the way down to one moa. )
The biggest difference, IMHO, between the two types of sight is apparent movement on target. Using iron sights a shooter can get the feeling that the sights stabilize, stop moving, affording a chance for an accurate shot. THe shooter never gets that feeling with a red dot,,,,,the dot is always dancing. There is always a noticeable arc of movement. With practice that arc can be made quite small but it is always there.
Pete

 

[Hangingrock]

The December issue of the NRA American Rifleman has an interesting article (Optics Ready:The Mini-Reflex Revolution)