Disappointment vies with confusion.

[Pond, James Pond]

A few may have followed or posted on a thread a while back concerning why I was missing my 300m target with a .223 AR.

To cut a long story shorter, I had zero'd at 50m, got hits on paper at 100m, but everything seemed low, and off paper at 300m

Following suggestions on the above thread, I decided to go for a 15-20m zero and played around with my Strelok app with different zero's to see which would also give me an approximate zero at 300m. Admittedly the BC was a guess based on seemingly typical BC values for a .223 55gr FMJBT (0.2). Humidity I left s standard and temp was recorded as 15c whereas it was probably closer to 5c.

All the rest, I had measured. 5cm bore to scope centre, 2980fps.

18m seemed like a likely candidate, so I zero'd there, shooting off a bench. I shot more off the bench at 100m and after playing around with holdover, I realised that the strikes were all about 25cm above POA, so about 3cm higher than my Strelok prediction. The group was OK. Probably about 10cm across.

So this was all within the realms of the ballistics calculator so off I went to the 300m section. 20rds, prone, with the forearm in a rifle clamp and when I went to check may target it was..... pristine.

Not a scratch. I had expected the hits to be around the centre, but there was nothing. The only damage I achieved on that target were the stapler gun holes.... I also had no point of reference beyond the target as the plywood backing was shot to hell by previous users.

So just don't know how to proceed and what to conclude. I really thought, with the 100m results, I'd at least be on paper, but alas no. THis means that this M400 still is not set up well enough to be a race AR in IPSC comps.

Feeling a bit down, frankly....

[Jimro]

Relax, it isn't the end of the world. Ballistics calculators require good input to give good output, so any guesses, uncertainties, and unknowns will trip you up.

Next time you go, zero at 100 yards, but adjust so your point of impact is 2"/5cm above point of aim.

At 300, aim dead on, but take a big piece of cardboard to use as a target backer. The backer is very important, as it will let you see impacts off the target. A refrigerator box is about the right size, but you can unfold all sorts of cardboard boxes to make a backer for easy transport.

Once you get on target at 300, record your zero, then get good data on 250, 200, 150, as well That will tell you more about how the load you are using is performing in your rifle than a ballistics calculator.

You'll be fine, stretching the legs of a rifle isn't easy the first couple of times.

Jimro

[krimmie]

300 meter hits from a stapler is pretty impressive.

[jmr40]

Use a bigger target. Put a large sheet of paper behind the target. Poster board, a newspaper etc. Anything large enough that you cannot miss. You may find you are shooting decent size groups, just say off in one direction.

[Pond, James Pond]

Good points on the backer and a different zero might be an option but I am just puzzled that my bullets were, in real terms, 25cm above POA at 100, but add another 200m and they drop of the board altogether. That is at least 40cm drop relative to 100m. It just seems a lot for .223 especially after reading all the posts about the 10" pipe zero principle...

.308 was a breeze by comparison: aim at the centre and you get hits on paper!

300 meter hits from a stapler is pretty impressive.

Once I'd compared the costs of staples to .223, it was a no brainer and it seems practice makes perfect!

[2damnold4this]

If you are 25cm high at 100, you may have shot over the paper at 300.

[2damnold4this]

link

[Jimro]

25cm high at 100 is almost 10 inches high.

A 55gr FMJ at 3000 fps, 9.8" high at 100m is zeroed at 17 and 390 meters (with sight height at 2.5"). It would pass above point of aim at 300m by 13 inches. I don't know your exact load, but you'll get it next time.

Don't get discouraged, take it as a learning experience and move forward.

Jimro

[Pond, James Pond]

Thanks for the link, 2damnold!

Don't get discouraged, take it as a learning experience and move forward.

You're right, of course and I'll be over it by tomorrow, but essentially I am always flying by the seat o my pants over here, whether it muddling through a zero or trying to work out loads from random, unlisted components. I would not be entirely against something working out as expected once in a while...

I think I will go back to the 100m range, and bring POI down closer to POA.

It may be that my hits the first time round were also high at 300, not low.

This virgin backing surface is a must I think. Otherwise, I really am just flying blind... A bit like my bullets, really!

On a plus side a shooter with clearly to much money left a dozen once fired Lapua .308 cases behind! Every cloud....

[44 AMP]

back in the mid 1970s, when I took basic training, the Army had us "battle sight zero" our M16A1s at 25 meters.

This was using the original 55gr ammo, at a claimed 3200fps. The target was unusual, having an odd shaped center to line the sights up on, and the bullet impact was (If I remember right) some 2-3 inches below where we were told to aim (there was an "x" on the target where the bullets were supposed to hit).

This put our rifles "on" at 250 meters (or so we were told). It did work, as we found out on the range, but none of the targets we shot at long range were bullseye (scorable) types, the were all man shaped pop ups that went down when hit.

A bullet crosses the line of sight twice, once at close range (on its way "up") and once at the target at the range you are sighted in for (on its way "down").

If you are too high, or low at the close range, you will be at long range, too.

[Pond, James Pond]

If you are too high, or low at the close range, you will be at long range, too.

All I can really say is that at 18m, I was hitting the POA dead on (as one would hope at 18m, with a scope!!). At 100m, I was about 25cm high.

So this implies, to me at least, that the bullet was either still in the upward arc, or coming down after apexing, but I can imagine it was that far from that apex.

Earlier posts suggested that the .223 bullet might still have been in the upward arc even at 300m making me hit higher still than 100m at that distance.

I have no idea if this is feasible, but it seems to show that I lack sufficient information to make my ballistics calculator reliable at making accurate predictions of what my bullet will do.

[Mobuck]

You only need to be 4-5" high @100 yards to be in the ballpark @300. I sometimes use a 20" Hbar .223 for shooting critters off my baitpile @350 yards. It's only around 4" high @100 BUT it has a carry handle mounted scope(being that high above bore changes the whole POI ball game). With 25 cm high 100 yard POI, you're lucky you didn't land a bullet in the next county.

[JR_Roosa]

Here's how I zero my rifle...it's really easy.

Start with a big target at 100yds. Either a 100yd reduced highpower target or a bullseye pistol target. You want one that is about 2.5ft x 2.5ft. That gives you +/- 15 MOA from center at 100yds. If I'm not on paper with that, I move it back to 50 to figure out where I'm missing. Either that or I bring a spotter along to walk me in.

If you buy a few of those targets, you can reverse them to cover the backer to get a nice clean field should you be way off, but I don't think you will be. They are easier to carry than cardboard.

You want to find your 100yd zero; don't complicate the math with "x inches high at 100yds." Once you have that, you should be able to better estimate your drop to 200 or 300 yards. You should only have about a 2 minute drop to 200, and another 3 minutes to 300, ballpark.

Your big target will give you +/- 7 minutes of paper at 200 (you should still be on paper with your 100yd zero, probably 4 inches low). These targets will only give you +/- 5 minutes at 300, and your 200yd zero should still be on paper, probably 9 inches low at 300.

Make sure your ballistic program has the ability to add in your sight height. That is the distance from the center of the bore to the center of the scope. The "25yd zero" trick is only good for rifles with the sight height of an M16 and standard ammo with a standard barrel. I feel that it has no useful place in civilian shooting unless you have a very close approximation of a GI rifle and GI ammo and nothing but a 25yd shooting range.

It might be useful if you make your own 25yd zero. Get your 300yd zero dialed or whatever range zero you want, and shoot a group at 25yds. Measure how far off the line of sight you are, and you now have a 25yd zero you can quickly check if you bang up your scope or otherwise mess with the rifle. That zero will only be good for that particular ammo though, unless you verify with testing that other loads are comparable.

Also, if you aren't really comfortable with the concept of MOA, read up on it a little on wikipedia or other online shooting articles. It's not intuitive, especially if you never really got into math/science/engineering.

Good luck! Like anything else, it gets easier after you screw it up a few times. I was just sighting in my daughter's AR, and I spent half an hour lowering the front post to bring down the group. Turns out that's totally backwards, and the groups kept getting even higher.

-J.

[hartcreek]

Over here we can buy paper on a roll at the craft stores. Used to get butcher paper and use a coffee can to trace around for the bulls eye. A roll of masking tape can be used to patch the holes. I am having similar problems as you using my cast bullets and getting my new scope adjusted on my 721 but I will get it back on paper in the spring as it is too cold outside to mess with it now.

[Pond, James Pond]

Also, if you aren't really comfortable with the concept of MOA, read up on it a little on wikipedia or other online shooting articles. It's not intuitive, especially if you never really got into math/science/engineering.

Once more I agree; it seems a biiiiig target backer is the way forward.

With MOA, I understand it all when looking at 100m (or yd) increments. What throws me is when I start trying to work out clicks at 20m for example. In that situation, I just use trial and error... with an emphasis on error!!

[stubbicatt]

OP I don't know if this will be helpful, but from a 200 yard zero, IIRC, my come up to 300 was 3 or 3 1/2 minutes. Sorry I don't remember my 100 yard to 200 yard come ups. It should get you pretty close though.

[MrBorland]

Using your MV and sight height, and a BC of .260, the ballistics calculator I use indicates you ought to be hitting 14cm high at 100m for a 21/300m zero. To be hitting 25cm high at 100m, the calculator tells me you'd be hitting over 30cm high a 300m. As others noted, a big cardboard backer would've told the tale.

Sighting in by setting your zero at such a short distance (18m) isn't going to be very accurate if you're using it to extrapolate to a much longer zero. I'd zero by shooting at 100m, making sure you hit about 14cm high. Or heck, just zero at 300m.

[marine6680]

Did some playing around with a ballistics calculator.

If you have a 55gr fmj boat tail, I used hornady for the BC. (.243)

Speed 3000fps (914m/s)

50m zero


With those numbers, your second zero is 175m, with a drop of 31.5cm at 300m.

That zero shoots pretty flat out to 200m, but drop starts getting larger quickly.

A 25/300m zero puts you on at those distances, but you will shoot high in between. With a maximum of 19cm high.


The problem with most zeros available for 5.56/223, is that drop past 200m is going to require a bit of compensation. You are unlikely to find a zero that works at all ranges you want to shoot.

I think a 50m zero to allow a single hold getting you within a few centimeters out to 200m and then making click adjustments or holdover for shooting out to 300m being the better option.

If the reason you want a good zero is for competition with several different ranges in a stage... The closer ranges are where you will make the most points and have the best speeds, the longer ranges will result in more dropped points. Most likely you will not be using premium ammo for the competition unless you get very serious with it. At 300m cheap ammo fired from a test platform will likely be grouping around 20-23cm or between 2.5-3moa... So already you are at a disadvantage at that range.

Use a zero that gets you on at your lower ranges, and requires minimal adjustment/holdover at ranges between 0-100m. Those are the distances you will be most accurate.

[g.willikers]

Did anyone mention the wind?
Misreading it can cause plenty of misses.

[44 AMP]

All I can really say is that at 18m, I was hitting the POA dead on (as one would hope at 18m, with a scope!!).

Bullets hitting exactly where you aimed at short range, that is why you were "off" at long range. Or, more correctly, you were off, at the range you expected to be on.

We have all the pieces, I think, we just have to fit them together so we can see the picture of the finished puzzle.

Line of sight is a straight line. Bullet trajectory is an arc, compared to the line of sight. Starts below the line of sight, at the muzzle, arcs up, passing through the line of sight at a short range. Keeps going up, flies over the line of sight, then arcs down, and falls through the line of sight at longer range, and keeps falling.

(if I'm preaching to the choir here, please bear with me)

A quick look in a Hornady book for 55gr .224 @ 3000fps,
You shot at 100 meters and your bullets hit 25cm high, (above aiming point), Right?

That load hitting there should be about 15cm low at 300 meters (bullets hitting below aiming point). If you were hitting exactly on your point of aim at 100meters, the bullets would be 40cm LOW at 300. (drop numbers rounded off)

I can't tell you how to calculate where the short range "zero" is for what long range "zero" you want, I don't know. I can tell you someone knows how, just not me. I can tell you that with bullets hitting point of aim at 18meters, they are also hitting your point of aim somewhere else down range, but as you found out, its not 100, or 300 meters.

The idea of a large backer for your targets is the best (and easiest) idea, being able to see what the bullets are really doing is worth more than calculations to most of us.

My book says (yards /inches) 100/0.0 (right where you aim) 200/ -3.9, 300 /-15.6, 400 /-38.4, 500 / -77.3, 600 /-137.5 (convert to metric if you want)

Note that the bullet seems to be falling faster, the further it goes. See how the drop at 400 is much more than twice the drop at 200. It looks like its not a constant rate, but that is an illusion. The bullet is dropping at a constant rate (gravity), it is the difference in the time it takes to cover the distance that changes, not the actual rate of drop.

Confused enough yet?

[2damnold4this]

I think Jimro's theoretical load comes closest to matching what happened as it seems pretty close to Pond's results. Both hit 25 cm high at 100 meters. one was dead up at 17 meters and the other at 18. Jimro's load was 33 cm high at 300 meters and we can assume that Pond's load was probably about the same.

I'm sure that Pond will get this worked out at his next outing.

[Pond, James Pond]

I'm sure that Pond will get this worked out at his next outing.

I hope you are not one to gamble: I'd hate to lose you money!!

Confused enough yet?

Let's just say that in terms of the thread title, Confusion now has Disappointment in a full-nelson and Disappointment is trying to tap out.

OK, seriously: Plan F, or was that G...

-Go to the 100 range and zero in there for POA/POI hits.
-Go to 300m, see where they are landing with a big cardboard backer for -added margin of error.
-Re-zero at 300 now that it is hopefully in the general ball park.
-Return to the 50m range and walk in with shots aimed at the X ring until they hit so I know my upward arc zero too.
-Go back to the 100m range and see where they hit now....

That is going to be a day when I blitz my recommended 10,000 steps:

To check your target at 300m, you need to pack and secure your gun, walk down a long corridor, walk down a long lane, walk down another long corridor, retrieve your target, check it, reverse the process to get back to the firing line, shoot some more and repeat until I know I am in the Alpha zone at 300. Huhh!

[jglsprings]

Maybe your heart rate and respiration from all that walking is what is screwing you up?



This is what makes shooting so much fun. Figuring it out and making it work for you.

[JR_Roosa]

MOA in a nutshell...

Everybody gets a little confused on MOA closer than 100 yards. Don't worry about that.

So MOA doesn't measure distance, it measures angles. Imagine a long skinny triangle with your gun at the point. The triangle gets wider the further you go away from the gun. The angle at the point stays the same.

One minute if angle (MOA) is simply 1/60th of a degree. It is conveniently really close to 1" at 100 yards. (2.5cm at 100 meters or so). As you get closer to the rifle by half or a quarter, one minute equals 1/2" at 50 yds, 1/4" at 25 yards, 3/4" at 75 yards, and 0.18" at 18 yards.

As you go further away the triangle gets bigger. 2" at 200 yards, 3" at 300, 4.37" at 437 yards, etc.

This means that if you know how many minutes per click on your scope (sometimes marked at 1/4" or 1/2" on the turret, assuming 100 yard sighting distance...these equal 1/4 minute and 1/2 minute of angle), you can translate that to how far you need to adjust the scope to get what you need with a little basic multiplication.

Here's an example. I tried a new hunting load in my rifle with one minute clicks on my sights last week. I shot a group 5" high and 2" left at 100 yards. 5 clicks down and 2 clicks right and I was perfectly centered for the next group. Done zeroing in 10 shots. That was easy.

My buddy came to a 600yd prone match with a new rifle. He was shooting a .223 with 55gr fmj bullets. He never got a great zero, but was "on paper" at 100. He has 1/4 minute clicks on his scope. I measured his sight height with a ruler on my Leatherman tool, entered that and a generic 55 gr load into JBM ballistic on my phone with a 100 yard zero. It gave me something like 14 MOA low at 600yards. We ran the scope up 56 clicks (14x4=56) and he happened to hit the X ring first shot (total luck). I was confident that if he was close on paper at 100, that we could estimate well enough to stay on paper with the 6'x6' 600 yard targets. They are almost 12 MOA high (6" is one MOA at 600 yards) and the computer/ballistics shouldn't be off by that much.

Keep thinking in MOA and it will make your life much easier.

J.

[Palmetto-Pride]

I just wanted to add that any ballistic calculator no matter how good it is even with perfect data put into it is not going to be exact they will get you pretty close, but nothing will compensate for real world shooting at various ranges. Also there's a saying with ballistic calculators and that is "garbage in garbage out" the most important data that needs to be as close as possible is, muzzle velocity, bullet BC, bullet weight, sight height above bore then the atmospheric conditions.