The rifle has a 2.5-10X scope, zeroed to 100 yards. What distance would you set a zero-magnification red dot for? 25yards? 50?

Is it a separate parallax free optic like a RMR or the low power setting on the scope? And if it’s the low power setting on the scope, is it FFP or SFP?

I zero all of mine at 50, as my intended use is likely to be inside of 200, at the most maybe 300, and that zero provides me with minimal deviation in point of impact across that range. It's simple to remember the trajectory for defensive use, and it also lends itself well to the square range at my gun club as our rifle bay goes out to 200 with 25 yard increments.



There's no single best option...just pick one that works best for you and your intended use, and know your impact points across your likely range of engagement.

I used to do 25yards, but that's kind of a mess when you start to reach out:

Separate unit.

Yep, I agree with 50 yards.

Whatever you zero it at it's very important to know the poi as posted in the great pictures above.
I personally prefer the 50 yard zero as it is easiest for me to remember and works within the confines of the ranges I'm most often shooting at or planning to be shooting at. Especially given my crappy eye sight.

50 yards it is, then. Thanks for the input, everyone.

50 or 100 yard zeros will be the best option for basically all standard .223/5.56 AR-15 rifles with unmagnified red dot optics.

A 50 yard zero keeps the bullet within a couple inches or less above or below the dot out to 275ish yards, and you won't be shooting much past that with an unmagnified red dot, especially on a defensive rifle. It eliminates the need to think about hold over/under for all practical defensive purposes; just put the dot on whatever you want to shoot out to 250+ yards.

100 yard does similar, keeping the bullet within a couple inches or less below the dot out to 200ish yards. Same ability to just put the dot on whatever you want and get easy hits out to 250, but you do give up a little bit of the longer range dropoff in exchange for only ever having to worry about hold-over (never hold-under) when taking extremely precise shots. But most AR shooters won't have to worry about such precision, or holding over/under by a couple inches at range.

Therefore, 50 is the more practical choice for most folks, plus it's easier to zero at 50, since some people can struggle when zeroing at 100 yards with their errors being further magnified by the longer distance.

For consideration

https://youtu.be/jttB1kUXfJE

92fstech - Thanks for posting the details in your response. Great information that I will be using for my own personal weapons. Mark

quote:

Originally posted by sigarmsp226:
92fstech - Thanks for posting the details in your response. Great information that I will be using for my own personal weapons. Mark

No problem. Just keep in mind that while those diagrams are generally correct, they are assuming a specific bullet shape and muzzle velocity, which may vary a bit from rifle to rifle. It's a useful guide that will almost certainly get you in the ballpark, but be sure to confirm on the range with your actual load and rifle.

I took my 16" M400 work gun out a couple of weeks ago (zeroed at 50) and ran it over a chronograph with some new ammo we got for work. I'm only getting 2950FPS at the muzzle out of that barrel with that load (had to go up to a 20" rifle to get 3100), and the intersecting zero point is closer to 175 yards than 200. Still within less than an inch at 200, though, if I could shoot that well .

50 or 100 yards. Shooter competency, intended use, quality of ammunition, range availability are all factors.

I prefer 50 yard on dots for the approximate 200 yard far zero. I say approximate because your 50 yard zero's far zero is totally theoretical until you confirm it. Most people do not have access to a place to do that. Others do not have the ability behind the gun. Your barrel length, shooting position, optic height, dot size, ammo selection, and countless other items will affect the far zero.

The advantage to a 100 yard zero to many people is that it is fairly flat, but I see that as something of a weakness. Is your gun really zeroed for 100, or is it 95? Or 107? Or 98? It probably doesn't really matter, but that flatter trajectory, at least in my mind, takes some of the precision of the zero away, especially with all of the compounded variables and especially with a red dot.

At a certain point, though, it's all academic. If you can shoot, your choice of zero probably doesn't matter. If you can't shoot, your choice of zero definitely doesn't matter.

Honest question.
Can anyone here shoot out to 200 with an non magnified red dot well enough to discern a difference between a 100 yard zero vs a 50 yard zero?
I've hit plates at that distance and can do so 2-3 times out of 5 on average. But for anything close to getting onto a 2-3 inch group I'd need some magnification.

Yes.

I can see the difference between a 50 yard and 200 yard zero. The 100 is noticeably low at 200.

Wow.
What kind of group can you shoot at 200 with no magnification?
With my shitty eyes I can probably keep them all on a 30" target. Probably.

I have a pic of a 5 shot group from last August that is strung left and right within the black of a B8 from last fall. Up and down it is about 3/4 the height of the 10 ring.

My 50 yard zero printed about 2" high at 100 yards.

My 50 yard zero printed about an inch high at 200, which surprised me.

This data is very consistent with the diagrams above.

For reference the 10 ring is 3.36" and the 9 ring is 5.54".

All shot off of a bag from prone. Gun was a 12.3" Ballistic Advantage barrel with a Turbo K.

I find that the absolute key to getting groups is consistent cheek placement on the stock. Even at closer distances, shooting five rounds, coming off the stock, and back on for five more rounds will produce two distinct groups, even though they may overlap and be close.

All dots get a 50 yard zero no matter what their purpose is, all magnified optics get a 100 yard zero.

quote:

Originally posted by clubleaf206:
The rifle has a 2.5-10X scope, zeroed to 100 yards. What distance would you set a zero-magnification red dot for? 25yards? 50?

quote:

Originally posted by DaBigBR:
I have a pic of a 5 shot group from last August that is strung left and right within the black of a B8 from last fall. Up and down it is about 3/4 the height of the 10 ring.

My 50 yard zero printed about 2" high at 100 yards.

My 50 yard zero printed about an inch high at 200, which surprised me.

This data is very consistent with the diagrams above.

For reference the 10 ring is 3.36" and the 9 ring is 5.54".

All shot off of a bag from prone. Gun was a 12.3" Ballistic Advantage barrel with a Turbo K.

I find that the absolute key to getting groups is consistent cheek placement on the stock. Even at closer distances, shooting five rounds, coming off the stock, and back on for five more rounds will produce two distinct groups, even though they may overlap and be close.

Thanks for the info.
That's one thing I've heard from a lot of shooters that the poi diagrams are very accurate and consistent. I'm a long time pistol shooter and very new to rifle and carbine shooting. I thought there'd be more overlap with skill set but it seems to be far more challenging than I expected.
Having to put more rounds downrange for practice and talk with other folks about how to shoot better is a good problem to have though.

Not a smart ass answer but.. sight it in for the distance you think you're most likely to shoot it. Then learn where it shoots at the less likely distances. (and write it down)
Who cares what the text book answer is.

quote:

Originally posted by cas:
Not a smart ass answer but.. sight it in for the distance you think you're most likely to shoot it. Then learn where it shoots at the less likely distances. (and write it down)
Who cares what the text book answer is.

Well, assuming that the "most likely distance" is 10 yards and in, I'd say that zeroing for that distance is a terrible plan.

The trajectory of 5.56 at varying zero distances is very well established.

Go with the data.