I purchased a Burris FastFire 3 for my Core. This is my first experience with a reflex on a pistol. I have a question about zeroing it in.

Should the dot (3 MOA dot) line up exactly with the top of my sights? I can cowitness the top of the sights. Or should the dot be up and on it's Own.

I put a couple hundred rounds through it yesterday and didn't have to adjust it. I was hitting the bulls eye pretty regurlarly. However, if I had the dot a good bit above the sights, I was off,if I put the dot roughly 1/8" above the sights, I was fairly accurate. That makes me feel like something isn't right. I assumed you put the dot on target and that's all she wrote.

Being my first experience, I am sure I have plenty to get use to and some adjustments need to be made.

That's called parallax. Nothing is wrong. Your sight picture has to be consistent when using this type of sight. Red dot sights are not like lasers

You don't zero the red dot with the iron sights. You adjust the red dot to the target. Put the red dot on the bullseye, bench rested and very stable, take a shot or 2 and then adjust your sight until POI macthes POA.

The beauty of the red dot, is if the dot is visible in the window and on target that is where the bullet is going.

You'll find that once you sight it in this way, it will align with the iron sights. But treat it like any sight and align the sight with your target, not with other sights.

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Something really smart

"You'll find that once you sight it in this way, it will align with the iron sights. But treat it like any sight and align the sight with your target, not with other sights."

Exactly. The red dot will NOT co-witness unless your iron sights are as high as the red dot. You have 2 differing sighting systems now. It's not the same as "co-witnessed" sights on an AR for example....have fun.
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CERAKOTE Svcs.
Class 01 FFL

Some factory iron sight systems on defensive pistols have you cover your intended Point of Impact with your front sight. Thus your front sight actually covers where your bullets hit at defensive ranges, like 10 yards and closer.

Other systems are set up for the impact to be just above the front sight, especially target guns. You need to find out how your sights work.

Step 1: With the red dot off, if you can align your front & rear iron through the RDS, do so, rested. See where your 5-shot group (PoI) is in relation to your PoA. Adjust your iron sights if necessary to center your groups (windage) and find out where they hit for elevation--under your front sight or above it.

Step 2: Align your RDS with the 5-shot groupings.

Now you have co-witnessed sights. Co-witnessed does mean when the two sighting systems are properly aligned with each other they WILL both be putting the bullets into the same PoI. However, the RDS is a stand alone sighting system that can be and should be used independently of the irons. It has a broader range of alignment capabilities than the irons.

So here's the advantage the RDS gives you:

If you put the dot in the upper right quadrant of the sight but on your target, look at your iron sights. See how they are "mis-aligned"? They are pointing to the upper right (where the dot is) and the two components of the irons will be somewhat low and left of the intended PoI.

Using just irons, you might not shoot because you have an ingrained perception that your sight misalignment will be inaccurate. BUT, the bullet will go where the red dot is, so the alignment of the irons is irrelevant. You learn to ignore your irons and concentrate only on the dot. The irons and the dot are actually, really, always aligned, but not in the classic sense that you have been taught is "sight alignment".

While using just the irons, your sight alignment has to be precise, as with any accurate shooting.

However, as stated by others, your red dot can float independent of the irons within the window, not just aligned with the irons, and still put the bullet on the target where the red dot was when the bullet left the barrel. This gives you a greater margin for error in sighting, which makes you faster. You will probably get smaller groups with good iron sight alignment, but you will be slower.

You may disadvantage yourself with a lower end optic like the Burris Fast Fire. Yes, it works, as do cheap self defense guns like Hi Points and Keltecs. Will they give you the results you are looking for? Probably to start, but if you have greater expectations, you will likely need to upgrade your hardware.

Thanks.

That's the idea CB3. If I like it I may pursue better equipment. Great explanation.

I have a Fastfire III, and I do not consider it a low end optic. It is a solidly midrange optic. I would not recommend it for a duty gun because it is not as tough as some higher end optics and its battery life is not as good. But optically I think the Fastfire III is fine. I am actually surprised how satisfactory it is too shoot with, and I don't think most people would shoot better by changing to a higher end optic. I have shot a lot of small things at 50 yards with the Fastfire III, and it does fine.

I also have an Aimpoint micro on a target pistol and a larger Aimpoint on a rifle, so I have some experience with quality red dot sights.

Spend some time getting comfortable with the Fastfire III before you decide whether to upgrade. And if you do upgrade, put the Fastfire on a .22 pistol or rifle. You'll have fun with it.

Oh, I wouldn't be upgrading any time soon. I am experimenting with this type of setup. I need much more time to adjust to it. I am still training my vision to not stare at the dot. Hard habit to break. I simply need more time. I am not sure I truest nderstand the benefits of the optic yet. Yet...

It takes some time to get use to, but is worth it in the end. I've been shooting reflex sights on handguns for just over 2 years now and see the many benefits.
Advantages: easier for aging eyes to see, easier to acquire with shooting on the move, low light/no light advantage, and both eyes open allow a larger field of view.
Good luck and keep after it.

The key to how fast you can learn to pick up the dot is how well you naturally point your pistol. No matter what your sighting system, you will shoot faster if when you extend your pistol out in front of you, either one handed or two handed, the sights naturally align.

Dry practice reps at home, dozens at a time, will get you there. All this can be done before you get an RDS and will make you a better, faster pistolero.

Turn off the RDS and practice aligning your iron sights as you present your pistol to full extension, even without a target.

Once you can do that consistently, then start pointing at a target and making sure your sights line up.

When you can do this, put up 2 or 3 targets and practice moving between them, keeping the iron sights aligned.

THEN turn on your RDS. Continue to focus on aligning your iron sights as you present the pistol to the target, and you will see the dot clearly in the window, co-witnessed.

You can now shift your focus to only the target, ignoring your iron sights, and the dot will be there. Now your practice becomes target focused, rather than sight/target focused. It's quicker and easier, but first you must master consistent on-target presentations. This is a skill that benefits all types of pistol shooting. The RDS just simplifies and enhances it.

In what way is co-witnessing different between a CORE and an AR?