Sighting Rifles 25 vs 100 Yards

[etrain16]

How's your shoulder feel?

Fantastic! I learned the 'sweet spot' on my shoulder where I can shoot it with no problem. But when I get off that spot, I feel it. The Service Rifle events you shoot 52 rounds over the course of about 90 minutes. Honestly, for a .30-06, it doesn't kick all that bad. I recall the .30-06 bolt gun I fired long ago was more punishing. Heck, I think I get more punishment from my shotgun.

 

[v0lcom13sn0w]

In my scope manual it tells me that sighting in at 50 yards is the same zero at 200 yards. I'm not sure, but I would assume that the same would hold true for a 25 yard zero to say maybe 150 yard zero.
Awesome grouping by the way!

it depends on caliber. my 5.56 AR has a 50 yard zero with 55gr FMJ ammo which means it shoots the same at 200-220yard. IIRC with a 25yrd zero it shoots the same at 350-375ish yards. i am not sure what the trajectory is for 30-06 though.

 

[NoLimePlease]

it depends on caliber. my 5.56 AR has a 50 yard zero with 55gr FMJ ammo which means it shoots the same at 200-220yard. IIRC with a 25yrd zero it shoots the same at 350-375ish yards. i am not sure what the trajectory is for 30-06 though.

View attachment 302709

Correct. I was looking at the manual for the Leupold Mark 6 CMRW reticle in 5.56 x855

 

[etrain16]

I found one chart on the bullet trajectory for the .30-06. I need to do some more research when I get some time. If I'm reading this correctly, a 25 yard zero is close to a 200 (or just a bit further) zero, at least for this bullet weight and powder charge:

 

[OutlawHoss]

It's called a Battle Sight Zero, (Battlesight Zeroing the M16A2/A3/A4 (ArmyStudyGuide.com) (http://www.armystudyguide.com/content/army_board_study_guide_topics/m16a2/battlesight-zeroing-the-m-2.shtml)) and it generally is how the A2 sights are set up to be calibrated. On my AR 10, the BSZ is 50 and 200 yards with M118 ammo. If you do the ballistic chart on most 'battle calibers' you can find the common BSZ for it.

 

[PaulB47]

I use 25 yards for one or two rounds just to get a new scope or irons into the ballpark. I certainly would not consider it dialed in if I didn't try longer ranges. Hell I wouldn't consider it dialed in at 100 yards if (as usual) my far zero is actually going to be 200 yards. I want to find a 200 yard range to be really sure (my backyard range is only 100 yards so I have to hit a couple inches high on that).

The near zero can be 20, or 25, or 30 yards, or any other range, you never know for sure, there are a lot of variables. It is worthless for anything other than a rough starting point.

Ideally, if I am hunting deer, and I figure my outer limit is 300 yards, then I try shooting at 300 yards to verify the bullet hits where I expect it to, however many inches below the line of sight. Of course you determine the expected number here via a ballistics program or a reloading manual, using a chrono to get the bullet velocity.

 

[orygun]

I use 25 yards for one or two rounds just to get a new scope or irons into the ballpark. I certainly would not consider it dialed in if I didn't try longer ranges.

This is what I do. Get it centered at 25 yds and then shoot at 100 to dial it in. Small mistakes that you might miss at 25 are much easier to see at 100, or even farther out. I know guys that go hunting with a 25 yard zero, but I'm just not comfortable doing it that way. I want the peace of mind knowing I've eliminated more variance in my sighting/aiming than can be done at closer distances.

 

[ron]

Shooting the M-1 at 100 yards you need a correct size aiming target.
The SR-1 target is what you want. The size of the target black increases
with distance. 100-200-300-600 yard target black appears the same size
to the shooter. How you hold your sight picture varies. 6 o'clock "pumpkin
on a fence post"? "line of white"? or "center of mass" (navy hold)? Impact
will change from shooting off bench or slung into the rifle shooting prone.
A good rifle and ammo combination will hold the 10 ring. Center up your
windage adjustment by moving the front sight. After sighting in at 100 yards.
Count the number of clicks up from the bottom. Now set the rear elevator to
the 1 mark by lossening the left side screw. Count the number of clicks up
from bottom again and you should be aliened with the 1 mark. Now your rear
sight is calibrated. My M-1 I shot this weekend the elevator was correct for each
distance fired. 200-300-600 yards.
Several different things on a M-1 can be "tightened up" to improve accuracy.
That is a whole different topic. 200 yards "offhand".

 

[Medic!]

Shooting the M-1 at 100 yards you need a correct size aiming target.
The SR-1 target is what you want. The size of the target black increases
with distance. 100-200-300-600 yard target black appears the same size
to the shooter. How you hold your sight picture varies. 6 o'clock "pumpkin
on a fence post"? "line of white"? or "center of mass" (navy hold)? Impact
will change from shooting off bench or slung into the rifle shooting prone.
A good rifle and ammo combination will hold the 10 ring. Center up your
windage adjustment by moving the front sight. After sighting in at 100 yards.
Count the number of clicks up from the bottom. Now set the rear elevator to
the 1 mark by lossening the left side screw. Count the number of clicks up
from bottom again and you should be aliened with the 1 mark. Now your rear
sight is calibrated. My M-1 I shot this weekend the elevator was correct for each
distance fired. 200-300-600 yards.
Several different things on a M-1 can be "tightened up" to improve accuracy.
That is a whole different topic. 200 yards "offhand".
View attachment 303408

Very nice Ron.

I would just like to add a great starting point for 100 yd zero of the M1.
Bottom out the rear sights and move up 10-11 clicks.
This should be a very close starting point for center mass zero at 100YDS.

When you get it zeroed. Then listen to Ron's advice .

 

[Medic!]

I keep telling you guys this. But I will say it again.
Go to JBM's free on line calculator for all your ballistic info. No need to guess. Or follow the advice of others about there zero. Just plug in your info and find out the flight path.

Here is an example.

My 16'' M-4gery. Shoots XM-193 at 3175FPS when measured at 15' with my chrono.

With a Coa. of .269 and 2.6'' tall Iron sights. If I Zero at 60 yds. I'm also zeroed at 200 yds.
That's +.9'' at 100yds and +1.1 from 115yds to 150yds. [Top of its flight curve]. And -6.6'' at 300yds.
Nice and flat to 200yds!

Go to the JBM ballistic Calculator online and check the numbers.
Then enter your own! It's a great tool.

View attachment 303987

 

[CHLChris]

In my scope manual it tells me that sighting in at 50 yards is the same zero at 200 yards. I'm not sure, but I would assume that the same would hold true for a 25 yard zero to say maybe 150 yard zero.
Awesome grouping by the way!

No, it is the other way around. If 50/200 is the same zero (and even that is a just a rounded-off short-hand), then a 25-yard zero would make the next zero much farther out. I'd bet close to 275 yards. It also places the zenith of the trajectory probably several inches (maybe 5-6?) above line-of-sight. The 50/200 zero allows for a trajectory within 2 or 3 inches above or below POA from the muzzle way out to 250 or so. This is what I use.

 

[CHLChris]

Another thought here... If zeroing at 25 yards is important, because it is so much easier to see the target at that range than at 50 or 100, then think about making the POI about an inch (maybe .75" would be better) lower than POA at 25 yards. I think that would get you at a 50-yad zero without actually going out to 50 yards...or 200, either.

But, your group had better be able to be almost touching, since 1MOA at 25 yards is only .25". Otherwise you aren't really "zeroing", you're just shootin' and smilin'.

 

[Medic!]

Another thought here... If zeroing at 25 yards is important, because it is so much easier to see the target at that range than at 50 or 100, then think about making the POI about an inch (maybe .75" would be better) lower than POA at 25 yards. I think that would get you at a 50-yad zero without actually going out to 50 yards...or 200, either.

But, your group had better be able to be almost touching, since 1MOA at 25 yards is only .25". Otherwise you aren't really "zeroing", you're just shootin' and smilin'.

You think?

M-4Gery 3175FPS at 15''
Ballistic COA of .269
2.6'' tall sights.

At -.7'' at 25YDS I get the following.

-.7'' at 25yds
+1.0'' at 50yds
+2.4'' at 75yds
+3.6'' at 100yds
+4.5''at 124yds
+5.1'' at 150yds
+5.4'' at 175yds
+5.4'' at 200yds
+5.1'' at 225yds
+4.3'' at 250yds
+3.2'' at 275yds
+1.6'' at 300yds

And you are Zeroed at 320yds.

So your guess of getting a 50yd Zero buy shooting -.75'' low at 25yds is just a WAG.
But why guess? Why not use a ballistic calculator and know?

 

[CHLChris]

So what? So, I should have said 1.2" below POA? That wasn't my point. I was suggesting that zeroing at 25 yards was a bad idea, considering the height the trajectory goes at the zenith. And that maybe someone could zero at some point lower than point-of-aim at a closer distance to approximate zeroing at a farther distance.

Sorry, I was off in my rough math by .45". Or whatever, the real number is. And yes, my number was a wild-bubblegum guess. But my line of reasoning was sound.

 

[Medic!]

Sorry. No offence meant.

I was just pointing out there really is no need to guess at any of these ballistic questions.
Just punch in the numbers and press calculate.

 

[ron]

Wow What you left out of your calculation is the iron sights?
Since the normal 6 O'clock hold for 'Iron' distance between the center of the
target and 6 O'clock varies as the distance increases and the target black
gets larger. Throws off elevation by several minutes.
Not an issue with a scope holding on center of mass.

 

[CHLChris]

I don't understand. If someone is consistent, wouldn't they still stay the same trajectory, with a 6oclock or center hold? I suppose it depends on the size of the clock, so to speak. How far below center is considered 6oclock? Isn't that a handgun thing?

 

[ron]

The size of the target black increases with distance.
The diameter of the aiming black is a little over 6 minutes.
A target of the correct size is needed to shoot the iron sight
military rifle well.

 

[Doc In UPlace]

Here's how I approach the formula.

Select your ballistics (bullet weight and velocity) then select your ideal distances (for my AR it's 75yd near and that makes it 150 yd far) then zero at the nearest distance to choose the ideal spread for your desired range of fire so to speak.

In this way you'll know you need to hold a bit high for targets closer than your near zero, (because the bullet is ascending) and for those beyond your far zero because the bullet is now descending past that point.

Though it may seem like a "flat" trajectory if sampled over a short distance, it's gonna be an arc due to that pesky old gravity.

 

[scott_see]

If you can get to an Appleseed event, you'll get an invaluable education on sighting and marksmanship. It's two days of training and shooting from incredibly knowledgeable and helpful folks. $60 if I remember correctly. They throw in revolutionary war history lessons for free. They talk of the garand as being the finest fighting instrument ever made.