Red Dot vs A2 Iron Sights: My Most Recent Revelation

[Ranger30-06]

A few days ago, I put the next addition onto my AR-15: A nice little 4 reticle AIM red dot sight on top of the carry handle.

I sighted it in at 50 yards. I put about 120 rounds downrange, and whether I was standing or sitting, every shot hit the black area of the paper. It was nice being able to pop off the rounds and watch them hit the berm behind the target.

After this, I moved to the 100 yard range. I shot 30 rounds sitting with rest at a fresh target, and only one out of 30 hit. I took it back to the 50 yard, and it put all of the shots back on target. Completely confused, I switched to iron sights (have a see through carry handle mount) and proceeded to put every shot on target in the black zone.

The worst part of all of this is that I have absolutely no idea where the shots were going at 100 yards, yet every one was on target at 50 yards! I aimed above, below, left, and right of the target and still couldn't get a group going. Has anyone else ever had a weird problem like this?

 

[wally]

Did you focus your vision on the target or the dot? If the later its likely your problem.

You need to focus on the target and look thru the dot.

 

[Ranger30-06]

I always focused on the target. If I focus on the dot itself it really strains the eyes and I don't hit anything!

 

[Sky]

If I had to bet you rounds were impacting way high at 100 yards with a 50 yard zero from you carry handle mounted red dot.

A red dot on top of a carry handle did not work well for me. Did not have the time or desire to make it work; however I did mount the dot in front of the carry handle in what is called the scout mode and I was able to look through the iron sights and red dot and all the sighting errors went away. Use that weapon for brush hog hunting with satisfactory results; when shooting in this mode I just see the target and the dot appears telling me where the round will impact; Just a thought but seems to work well for me.

 

[rbernie]

If you mounted the optic on top of the carry handle, you were likely shooting way over the target at 100 yards due to the offset of the bore to optic.

--

ETA - beaten to it by Sky.

 

[wally]

I missed the bit about it being mounted on the carry handle.

May I suggest a quad rail or one of those "add a rail to your hand guard" kits (assuming your hand guards don't wobble). This way you might get the irons and red dot to co-witness to some degree.

This was my first red dot on an AR trial back when my old eyeballs started having trouble with irons:

I liked it enough I eventually swapped to a quad rail and a better red dot, that one is now on an AK side mount (with the lowest rings I could find) I use it on my 5.45x39 Saiga conversion.

 

[Ranger30-06]

Okay that makes sense now. Does anyone have an idea as to just how much it will be shooting over the target at 100 yards? (My range is a little weird the way you hang targets and how the berm is laid out).


Sky: As for the red dot being mounted on top of the carry handle, I actually kinda like it. It's far enough away from the stock so that your face barely even contacts the stock, so I was able to send rounds downrange extremely quickly without having to waste time re-finding the dot or losing it because of having a weird cheek wield or something.

I also found that having the gun set lower on my shoulder (due to the high red dot) allowed me to soak up the little bit of recoil there was to the point of there literally being no movement between shots; very nice for double tap drills and such.


Wally: I thought about one of those mounts. Unfortunately I'm close to broke right now with the car insurance rip off I just had to pay because I'm a good driver and apparently no one else in Jersey is. Back on topic though, I might try one of those mounts that attaches to the carry handle then drops off just ahead of it.

 

[holdencm9]

I am confused about the sight height.

The sight axis may be at most, say 4" above the bore axis. If you are hitting right on at 50 yards, that means the bullet is traveling at an upward trajectory to "meet" the sight axis. At most, at 100 yards, you would be hitting 4" high (assuming perfectly straight line trajectory which it isn't but let's say it is).

So if you are only a few inches high you are saying you had no idea where you were hitting. So there must be something else at play.

 

[madcratebuilder]

Back on topic though, I might try one of those mounts that attaches to the carry handle then drops off just ahead of it.

Have you thought about going to a flat top upper for mounting optics? A bare upper is under $100 new, less for a used one. Just swap your parts over. You get better cheek weld, less weight and a start for a A2 build with the old upper.

 

[Ranger30-06]

Have you thought about going to a flat top upper for mounting optics? A bare upper is under $100 new, less for a used one. Just swap your parts over. You get better cheek weld, less weight and a start for a A2 build with the old upper.

I considered it, but I don't have the tools to do it or a vice to hold it so it would get expensive quickly. Honestly though, I really like where I have the dot mounted for reasons stated in my previous post...


holdencm9 I may have been shooting 4" high and never noticed it... I didn't really have the patience to waste the ammo to figure out where it was shooting, and when I was able to throw rounds downrange more accurately with the irons, I just stuck with them.

 

[holdencm9]

holdencm9 I may have been shooting 4" high and never noticed it... I didn't really have the patience to waste the ammo to figure out where it was shooting, and when I was able to throw rounds downrange more accurately with the irons, I just stuck with them.

Okay, if that is the case then it is plausible. I got the impression you were WAY off the target and I thought, "now wait a minute...." If you are right on at 50 then you shouldn't be more than whatever the distance is from the sight axis to the bore axis. It sounds like some more testing is in store for you!

 

[BrocLuno]

I'd suggest re-zero'ing at 50 with the group at the bottom of the Bull. Then try the 100 again

 

[Z-Michigan]

The sight above the carry handle is almost certainly the problem. If you were perfectly zeroed at 50 then at 100 the bullets would have been about 2.8" high. However, if you were zeroed at 25 then the impact at 100 would have been 10" or more high. So if your 50yd zero was just a little high, your 100yd impact would be very, very high.

 

[Sam1911]

Sky: As for the red dot being mounted on top of the carry handle, I actually kinda like it. It's far enough away from the stock so that your face barely even contacts the stock,

That kind of sounds like you have no decent cheek weld at all. Sort of backwards for accurate shooting. Most rifle shooters want to be firmly planted against the stock in a solid, repeatable position, not hovering somewhere behind the sights just brushing against the stock. You certainly could have been just plain missing, shooting like that.

so I was able to send rounds downrange extremely quickly without having to waste time re-finding the dot or losing it because of having a weird cheek wield or something.

And that would suggest the very same thing.

Do you know any good shooters who could work with you and maybe shoot the rifle with you to help you figure out what's going on? Sounds like there could be several different issues compounding your frustration.

 

[Ranger30-06]

That kind of sounds like you have no decent cheek weld at all. Sort of backwards for accurate shooting. Most rifle shooters want to be firmly planted against the stock in a solid, repeatable position, not hovering somewhere behind the sights just brushing against the stock. You certainly could have been just plain missing, shooting like that.

Sam, that's the glory of a red dot: As long as you can see the dot, it's always exactly in the same place. You don't have to worry about paralex or cheek wield, because no matter how you see it, the dot is always on whatever you want to shoot. If you have a red dot, set the dot on a fixed small object, then move your head around. No matter what, the dot stays on whatever your aiming at.

I didn't have a single problem getting every round to hit the dot straight on at 50 yards, but I believe at a hundred I was probably shooting high like the others said. Because of how the range is laid out, I probably just couldn't see exactly how high I was shooting because I was keeping my eyes on the target and not paying attention to where they were striking the berm.

 

[Sam1911]

I certainly understand the virtues of a parallax free red dot. It doesn't entirely eliminate the necessity of good technique. Almost, but not quite.

The combination of bad cheek weld and "sending rounds downrange extremely quickly" does tend to give the reader the impression that one might be surprised if you HAD hit the paper at 100 yds. But maybe you were exaggerating.

Best of luck to you!

 

[Hardtarget]

maybe try a big piece of cardboard(4'X4') and mount the bull low so you can see the group even if its two feet high. Adjust to move impact to the target.

Mark

 

[benzy2]

Most cheap red dots are certainly not parallax free.

 

[Sam1911]

Ooooh, good point benzy2. Ranger, those AIM red-dots are like $35-$50, right? Are you sure they're parallax-free? That would certainly explain things is a big hurry.

 

[Ranger30-06]

Hardtarget: That's probably what I'll wind up doing next time I head out to the range.

Sam: The dot was $70. I just find it weird that it puts every hit dead on at 50 then I can't find the hits at a hundred yards.

 

[Sam1911]

Sam: The dot was $70. I just find it weird that it puts every hit dead on at 50 then I can't find the hits at a hundred yards.

Do you know if it is specified to be parallax-free? (And if it really is? $70 for an optical sight is crossing the line from inexpensive to down-right cheap. It will have limitations. You may be able to work with them, but they may trip you up sometimes.)

The problems would be easily magnified as the range increases.

Again, a known good shooter could help you test that out as well.

 

[Ranger30-06]

I'm not sure; I'll have to dig out the box later.

The other thing I forgot to mention is that it's an open hood sight, not a tube site. I'm not sure if that makes a difference but at least now I'll have some tests to perform when I can buy some more ammo for the range...

 

[Z-Michigan]

I wouldn't expect much from a $70 sight, regardless of what features it claims.

Re: open hood design, that just means that the viewing window and line of sight will be even higher. If this works for your purposes, great, but having an optic that high up makes things really screwy and complicates zeroing.