Zeroing At 50 Yards?

[phoenixcrash]

Ok guys, I just finished all the work on my custom M&P 15 Sport. Looks and functions great. Turned out much better than I had expected. I'll post pics soon. It's got the Magpul MBUS rear and front flip-up sights, and I picked up a Bushnell TRS-25 (brand new) for $70 (which I mounted on a 0.83" QD riser.

Here's the question I have; How distance should I zero my irons/red dot at? Everything that I've read and researched says that 50 yards. This distance is apparently used by a lot of people, including most LEOs. I live in the country, but the rifle is not for hunting deer at 100+ yards. I've got a Remington 700 to take care of that. There are several 9mm pistols and two Mossberg 500 8-shot pumps that will take care of home defense. So long and short range is covered. I want the AR15 to drop targets no farther than the distance of my property (3 acres), but still be able to use it inside of 25 yards if the need arises. In other words, I probably won't be firing at anything over 75-80 yards, but may need to engage at 15-20 yards. I had originally thought to zero the irons at 50 yards, and the red dot at 25. But, I thought the different elevation adjustment may be confusing in a SHTF situation.

So, given the job the AR has been tasked with, should I just zero the irons and the red dot at 50 yd, or the irons at 50 and the red dot at 25? Any help would be greatly appreciated guys.

 

[Tbat]

If it was me, whatever distance you choose to zero, I would use the same zero for both the iron sights and the red dot. It would just keep things simpler. It all comes down to preference, but a 25, 36, 50 or 100 yard zero would work for what you have described. My personal preference is for either a 50 or 100 yard zero.

Also for whatever distance you choose to zero, verify shot placement yourself, at other distances as well, because what you actually get may not match up exactly with all the charts/calculators that you will find on the internet for the various zeros and impact locations at other distances once zeroed.

 

[phoenixcrash]

Ok, I think I'm going to zero at 50, and then test it at different distances. I'm still open to suggestions though.

 

[OKFC05]

Rather than guessing, you can plug in your figures and see the whole trajectory.
Handloads.Com Ballistic Calculator

 

[ChattanoogaPhil]

Zero at 50 and be done with it.

If you are shooting between 20-80 yards it really doesn't matter much. You won't be much more than an inch below and above line of sight. At those distances, it really doesn't matter for critters, four legged or otherwise.

 

[phoenixcrash]

Okay guys, thanks for the input. And thank you OKFC05 for the link to the Ballistics Calculator. Zeroing in at 50 first thing in the morning.

 

[WA101]

Okay, I'm going to offer the counterpoint to the 50 yd zero. A good rifle is designed to place accurate shots at long range. The simpler zero is 100 yds or meters because it allows for precise shots of 223/5.56 at long range and an easy transition to short range because you're always in a hold-over condition from the 100yd zero regardless of range. A 50-yd zero means you need to do a hold-under for a precise shot at 100-yds and then transition to a hold-over at short range which you'll have to do regardless of your zero. As explained in the video below, this former Navy Seals prefers a 100 meter zero with a 5.56 rifle because it offers a flatter trajectory from CQB to 100 meters for precise shots at 100 meters and quicker transitions to other distances with more easily predictable hold-overs.

http://youtu.be/QtfAi5FTHZk

More from Kyle Defor's blog (copied from Ar15.com), which also discusses a 25/300 zero...

(5) The 300m zero in the military has given both the M4 and 5.56 a bad name, and here's why- Rarely are there any engagements at 300. But there are a lot at around 100. So a guy with a 300 yd zero who aims center at a target at 100 will miss high every time.

(10) It is almost impossible to find a man in the prone with moderate cover at 300 without magnification. So why would you zero at that distance? And to play devil's advocate, if I have a shot on a man at 300, and I have a 100 yd zero on my gun, all I have to do is aim slightly high, BUT...I have 300 yds to get it right, as opposed to having less than 100 yds to get it right if the situation was reversed.

(11) The 200 yd zero is called the fire and forget because of it's rise/drop of 3" from CQB distance out to 200. But what if you have a head shot at 100? Odds are you'll still miss. Also consider that rise and drop are related to the height that the optic is mounted off of the line of bore. This is a small deviation, but it still adds to the equation. I went to war with this zero and it served me well. I just now believe that the 100 yd zero is the best as it has a flatter trajectory from CQB distance to 100 yds. You'll also never be off more than the distance between line of bore and line of sight (on average 2.75"). I also like it because of ....

(12) Most people can SEE a head (or a 6" circle) at 100 yds, the AK-47's bottom zero is ...100, all snipers bottom out dope at...100.



Sent from my iPad using Tapatalk

 

[scooter123]

IMO WA101 has it correct. Due to high sight offset typical to the AR platform if you set your zero at shorter ranges you can end up shooting significantly higher at long range due to convergence between the light of sight and the bore axis. Try and zero an AR at 25 yards and you'll probably find yourself shooting 6 inches or more higher at 100 yards.

Now consider the effect of sighting the rifle in at long range. In this case there will be almost no convergence between the line of sight and the bore axis. So, at long range you either be dead on or in need of a slight holdover. So, if you really need to hit a target accurately up close all you have to remember to do is hold the sights whatever the distance of the sight offset is. If your sights are 2 inches above the bore axis you aim 2 inches high. The end result is that between 10 feet and perhaps 250 yards your point of impact will be within 2 inches of the sight center.

 

[Rastoff]

Well, this is one of those debates that will rage forever. Still, I'll jump in...

There is a lot of merit to zeroing at 100 yards if you're sure you'll never take a shot longer than that. The general height of an AR sighting system over the bore is 2.5". This means that if you zero at 100 yards, anything closer will be off by a maximum of 2.5" low. So, if you're shooting for self-defense and the guy is 50 yards away, the POI will be about 1" lower than POA. This will stop all the bad guys.

If you zero at 50 yards, the end result is almost the same. Using this zero will put you 1.5" high at 100, about 1" low at 25 and about .5" high at 200. This is a much more practically useable range than when you zero at 100.

Remember though, this is only better if you plan to go out beyond 100 yards. The drop increases exponentially once the bullet has passed the apex of its trajectory. So, if you zero at 100, which will use the apex of the trajectory for zero, and then need to shoot longer than 100 the hold over will be much more dramatic. Therefore, as long as your sure you won't shoot longer than 100, which is really unlikely anyway, zero at 100.

 

[sgtsandman]

I would zero at 100 yards. You match the zero to the round you are using and the ranges you expect to fire at. So, for most high powered rifles, 100 yards is the standard.

For rounds like .22LR or .45/70 Govt (out of a 18" barrel), 50 yards is a better match.

 

[cyphertext]

Get a rear sight that has elevation adjustment for known distances and zero per the instructions... problem solved.

 

[Tbat]

... There is a lot of merit to zeroing at 100 yards if you're sure you'll never take a shot longer than that....

If you zero at 50 yards, the end result is almost the same. Using this zero will put you 1.5" high at 100, about 1" low at 25 and about .5" high at 200. This is a much more practically useable range than when you zero at 100.

Remember though, this is only better if you plan to go out beyond 100 yards. The drop increases exponentially once the bullet has passed the apex of its trajectory. So, if you zero at 100, which will use the apex of the trajectory for zero, and then need to shoot longer than 100 the hold over will be much more dramatic. Therefore, as long as your sure you won't shoot longer than 100, which is really unlikely anyway, zero at 100.

Zeroing at 100 will allow you to do quite well out to 200 without much of an adjustment and out to 300 with a little more adjustment. It is after 300 that the other zeros outshine it.

I know all the charts and programs show that you should only be a couple of inches high at 100 with a 50 yard zero, but that was not my experience when I was using a 50 yard zero. I experienced 6 to 8 inches high at 100 with a 50 yard zero with three different AR 15's with 16 inch barrels, and with 1/9 or 1/7 twist.

Now that I have my AR 15's zeroed at 100 they are only about 2 inches low at 50 and not much lower at 200. It just seems to me that there is a much tighter grouping with less adjusting for distance with the 100 zero when shooting under 230 yards or so, when compared with the 50 yard zero. I couldn't duplicate the results shown in most internet charts with the 50 yard zero with various .223 or 5.56 commercial loads including green tips.

 

[phoenixcrash]

Ok, I see alot of difference in opinion and experience with a 50 yd. zero, and those who prefer the 100 yd. zero. I would like to throw this out there, just so everyone understands my situation; I wear glasses (which make shooting anything a pain in the ***), and I suffer from diabetic eye damage in both eyes. I can barely see the bullseye at 50 yards, so there's no way I'd be able to get close to a bullseye at 100 yards with a 1X red dot, let alone my irons. So, taking my ****ty eyesight into consideration, what would you guys recommend?

 

[ChattanoogaPhil]

Ok, I see alot of difference in opinion and experience with a 50 yd. zero, and those who prefer the 100 yd. zero. I would like to throw this out there, just so everyone understands my situation; I wear glasses (which make shooting anything a pain in the ***), and I suffer from diabetic eye damage in both eyes. I can barely see the bullseye at 50 yards, so there's no way I'd be able to get close to a bullseye at 100 yards with a 1X red dot, let alone my irons. So, taking my ****ty eyesight into consideration, what would you guys recommend?

I would recommend a magnified optic rather than 1x red dot. 1-4x scopes are very popular on ARs.

As far as zero... . there are no magic bullets. A ballistics calculator does not lie. It is what it is.

 

[phoenixcrash]

I had considered a magnified optic, but I wouldn't be able to switch to irons like I can with the 1X red dot. I can simple turn the brightness dial back one click with the red dot to turn it off, and then the irons are in perfect view. I couldn't deal with having to view my irons through a magnified optic. In fact, I tried that with my Primary Arms 4X Compact Prism Scope, and it looked horribly confusing. I ditched that idea immediately.

BTW, I apologize for the small amount of explicit language in my last post. I was unaware that it's frowned upon here.

 

[Rastoff]

I experienced 6 to 8 inches high at 100 with a 50 yard zero with three different AR 15's with 16 inch barrels, and with 1/9 or 1/7 twist.

Not if the gun is working properly you didn't. This had to be the result of shooter interference or a damaged barrel. I personally own three ARs and a Mini-14. I've shot many more. Every one of them that was zeroed at 50 yards shot about 1.5" high at 100yards. The calculators are correct. I've verified it on the range and thousands of other shooters have as well.

I'm not picking on you, but there was something wrong with those guns or the way they were being shot.

Now that I have my AR 15's zeroed at 100 they are only about 2 inches low at 50 and not much lower at 200.

Same thing here. If your gun is zeroed at 100 yards, it should only be hitting ~1" low at 50. This is due to the scope height over bore. It's how the gun physically works. If it were hitting lower than 1" at 50 with a 100 yard zero, the scope height would have to be higher than 2.5" and the speed of the bullet would have to be about half of a normal .223 velocity.

Something is definitely not right with you rifle. I wish you were closer as I'd love to shoot some with you and see what's going on.

 

[ChattanoogaPhil]

If you can't even see the bullseye at 50 yards, but you want to shoot the bullseye at 100 yards, what is the importance of having iron sights co-witness that which you can't see anyway. Why not use a magnified optic and enjoy shooting rather than struggling with not being able to see what it is you want to shoot? You can also use a QD optic mount to have immediate use of irons.

Besides, the 1x red dot is for fast target acquisition not precision bullseye shooting. Choose the optic best suited for what you want to do with the rifle and your capabilities.

 

[ChattanoogaPhil]

Something is definitely not right with you rifle. I wish you were closer as I'd love to shoot some with you and see what's going on.

All three rifles are a problem???

It's the shooter or the zero is not 50yds. 6in over at 100yds indicates a 25yd zero on an AR platform.

 

[phoenixcrash]

I CAN see the bullseye at 50 yards. I could probably see it up to 65-70 yards, but anything beyond that is futile. Like I said in the OP, this rifle will likely never engage anything farther than 75 yards.

Besides, the 1x red dot is for fast target acquisition not precision bullseye shooting. Choose the optic best suited for what you want to do with the rifle and your capabilities.

I would consider that to be very sound advice, sir; "To each his own". If it works for you and the circumstances of your given/likely situation, USE IT!!!

 

[Tbat]

No offense taken. I am always willing to learn something. I have never been one to take what I read or hear on the internet as gospel without verifying it myself, just funny that way. It would be good if one of you were closer as I would like to see someone shoot exactly like one of these internet charts.

However, it is not likely the rifles, or I would not think that three different brands would all have the same result. I do know the difference between a 25, 50 and 100 yards. I didn't shoot them from a bench locked in a vice but prone with a bipod (just a cheap Vietnam era type that clamps on the barrel). Others with varied shooting backgrounds have shot them as well and acheived the same results.

If the charts/calculators are so perfect how come everyone says verify at other distances? That means there can be some variation. Don't altitude, humidity and temperature have some effect? Can you point me to a video on the internet where someone actually shoots at other distances once their rifle is zeroed? If so, I would be interested in seeing it.

You can think it is the shooter if you want, but I know different. Opinions are like elbows, everyone has a couple of them. I may not be a world class marksman, high speed/low drag operator who stayed in a Holiday Inn last night, but I have shot enough I know that I can hit bullseye at the zeroed distance whether it be 25, 50, or 100 yards. I have shot with exmilitary, both Marines and Army, and they have never had to correct my zeros. With that said I know shooting ability/knowledge is not equal, even among military personel.

Furthermore, after zeroing at either 50 or 100 yards I will shoot at 25, 50, 75, 100, 150 and 200, just to check where point of impact is compared to point of aim. I only have slightly over 200 yards to work with on my range, so I cannot check greater distances.

Someone better tell all the deer, squirrels, rabbits, rats and other varmits, that I have shot over the last four decades, to get back up because they ain't dead because I don't know the difference between a 25, 50 or 100 yard zero, lol.

Not trying to start a pissing match, just stating my experience and observations because you always see someone saying do it this way and this will happen, but you don't always get to see the proof. They will video shooting one distance, i.e. the distance they are setting their zero and then just say this is where the bullet will hit at these other distances once you do this.