Help! Can't figure out where my bullets are going!

[Caimlas]

UPDATE: Help! Can't figure out where my bullets are going!

I'm having a problem zeroing my rifle. I can't figure out where the bullets are impacting, at all. Yes, I realize that this is very bad.

I've got a 16" Rock River Arms HBAR barrel AR15. I'm shooting 55gr FMJ Fiocchi through it. According to the Fiocchi web site, this ammo has a muzzle velocity of 3240fps. This is, apparently, 10fps less than the spec requirement for M193 (just looked this up), though I suppose it's possible the ammo falls significantly short of M193 and other military rounds.

I have shot this ammo @ 100 or so paces before w/ a cheap Leapers 4x scope, in this same rifle and have achieved ~1" groups, so I know it's "good" - at least good enough for that. Never shot beyond that, though, until now. (Said scope is no longer with us, so I'm working with the irons for now. Or, at least, trying.)

I have zeroed the rifle at 50 yards (Improved Battlesight Zero), according to the Maryland AR15 Shooter's Site information, which states:

12. This battlesight zero is valid to 300 meters for both the M16A2 and M4 Carbines and their AR15 sisters. It's valid with any ammunition that approaches the specs for M193 (55gr) or M855 (62g) Ball ammunition. It works for both rifles and carbines due to the offsetting influence of higher muzzle velocity in the rifle being offset by the longer sight radius that moves bullet strike less per click. This is battlesight, not X-ring shooting!

3. When zeroed at 200 meters, a distance twice that of normal combat engagements, these rifles have a very flat trajectory that is less then 2" from line of sight at all intermediate distances; a distance that's smaller than the normal dispersion of arsenal or factory loaded ammunition. This tiny trajectory arc allows very precise shooting out to 250 meters where the bullet is only 2" below line of sight.

( I used the "unmarked" aperture on my sights for all of the following shooting. )

So, after I zeroed the rifle at 50 yards (from prone) and was getting 1" groups (at 50 yards) about a half inch above the center of the target, I backed up to 100 yards. This also went well, considering I've never really shot at such ranges with iron sights (bad eye sight made me hesitant to even try/embarass myself).

The result was likewise "good": about 2-3" high from center of target, 2" to 3.5/4" or so "groups" of 5+ shots (from a bench) with no fliers. Not as good as I could do with a scope, but satisfactory none the less.

Sounds good, right? So I step back to the 200 yard mark; now I'm shooting at what is probably the extent of my vision, but the target I'm shooting at is still the same size as the one I shot at 100 yards (ie, it's something like 3/2 the size), more or less: visually, a little bigger than the front post, with the 2" orange dot sticker in the center just barely visible enough to 'cut' with the front post.

So, I shoot 6 rounds while visually cutting the orange dot in half with the top edge of the front post (same thing I did at 50 and 100 yards), and then walk back down to inspect the target. There were no holes on the target or the backing, or anywhere that I could see (at least, those that I'd made). Again, this is a big piece of paper - about 2' square. I step back to 200 yards again, and fire 3 shots (again, slowly) at the top of the paper target's top edge, and 3 at the target's bottom edge (in the hopes that I'd hit somewhere in the middle if it was shooting high or low). Again, nothing. One more try, this time about half a target's length below the target that much distance over the target would've been Unsafe, otherwise I'd have tried that too). Still nothing.

Frustrated to madness and with daylight fading, I pick up my stuff and then head up to the 50 yard line one more time to "finish off" the ammo I had. Twelve rounds later from the standing position, I had a 6" cluster of holes in the center of the target I'd been shooting towards/at from 200 yards (so the zero didn't get bumped off somehow between 100 and 200, I'm certain).

So, what the hell am I doing wrong here? I spent an hour this afternoon just trying to figure this out. Is there something wrong

(An aside thought: could this range be demarked in meters? It's a small personal range with just 1 bench at 100, 1 at 200, and a flag marker at 50 and 25. Pacing it, I'm about 5-10 steps shy of the 100 yard mark when I reach 100 paces, and I've historically been pretty good at pacing off distance. That'd make it a 220 yard range, which in conjunction with the ammo possibly being weak, would lead to the possible conclusion that the ammo is dropping off drastically between the "100" and "200" benches. Thoughts?)

Update 03-03-08:

I went out again today and was able to hit center-target w/o so much as much effort or sight adjustment (and none on elevation adjustment). Here's what I think was happening (let me know if I'm off my rocker on this):

Last time I went out, there was a ~15-25mph headwind. This time, there was a solid cross wind, about the same speed, coming from the right/south. I first thing I did was shoot at 100 yards - again, I was hitting vertical center, but about 2.5" to the left. I then moved out to 200, made a slight adjustment for windage, and shot. They were all exactly where they should've been, in the center of the target.

Only thing I can figure about the last time is that the combination of the berm directly behind the targets, and the 30mph head wind, created a horizontal vortex around 25-50 yards from the target (I noticed some wind eddies around there, and that's where the wind became noticeable). Only thing I can figure is that the wind slowed the progression of the bullet, and/or created a pressure differential which pushed the bullet up or down, resulting in a miss.

How's that sound? Plausible?

 

[jpwilly]

If I were you I'd pop the rear pin pull out the bolt carrier and bore sight at 200. I'm guessing but the bullets are either going over or under the target.

 

[Dave R]

You can always start by sighting in at short range. Even 5 yards, if necessary to get on paper.

Did the bore sighting thing make sense to you? Immobilize the rifle with lots of sandbags. Sight through the bore. Then adjust the sights to point where the bore is pointing. that'll get you pretty close.

 

[Caimlas]

Dave R - as I described, I'm dead on paper at 50 yards, and only a couple inches higher than that @ 100 yards.

Given that .223 should be pretty flat out and beyond 200 yards, I'm just wondering why I can't even hit paper at 200 yards, whereas 100 wasn't even all that challenging.

Yes, I understood the sandbagging concept. Might be a bit difficult w/ irons, but I could at least give it a try to see where things are pointing @ 200 vs. 50. (Ah, to find some sand bags.)

I was just hoping someone might have a possible explanation for the apparent discrepancy.

 

[Caimlas]

This is really getting under my skin, because there's something that doesn't make sense to me - namely, why I was missing. I've been shooting long enough to know when my sights aren't on target when I pull the trigger and when my breathing isnt right, and this isn't, as near as I can tell, representative of those problems.

Would a 15-25mph headwind (ie, blowing from behind the berm into my face) impact trajectory much/any, such as causing the bullet to dive? Berm is about 10-15' high, and the 50 and 100 yard firing positions may have been shielded by it somewhat. The 200 yard one was not, I'm sure.

There's also this trajectory info on the round (best I could find/guess, as I'm not sure of the round's BC):

Muzzle velocity: 3240 fps
Bullet weight: 55 grs
Ballistic coefficient: .250
Altitude: 2296 ft
Temp: 50 °F
Sight height: 2.5 in
Max range: 300 yd
Increment: 25 yd
Zero range: 50 yd

Range Velocity Energy Trajectory Total drop Flight time
0 yd 3240 fps 1282 ft.lbs -2.5 in 0 in 0 sec
25 yd 3145 fps 1208 ft.lbs -1.14 in 0.11 in 0.024 sec
50 yd 3051 fps 1137 ft.lbs 0 in 0.43 in 0.048 sec
75 yd 2960 fps 1070 ft.lbs 0.91 in 0.99 in 0.073 sec
100 yd 2871 fps 1007 ft.lbs 1.57 in 1.79 in 0.098 sec
125 yd 2783 fps 946 ft.lbs 1.96 in 2.86 in 0.125 sec
150 yd 2698 fps 889 ft.lbs 2.08 in 4.22 in 0.152 sec
175 yd 2614 fps 834 ft.lbs 1.89 in 5.87 in 0.181 sec
200 yd 2531 fps 782 ft.lbs 1.39 in 7.83 in 0.21 sec
225 yd 2450 fps 733 ft.lbs 0.56 in 10.13 in 0.24 sec
250 yd 2370 fps 686 ft.lbs -0.63 in 12.78 in 0.271 sec
275 yd 2292 fps 641 ft.lbs -2.22 in 15.84 in 0.303 sec
300 yd 2215 fps 599 ft.lbs -4.24 in 19.33 in 0.336 sec

So short of magic bullets which drop suddenly, what could it be?

Gosh, I'm seriously having a hard time that I missed a 2' square piece of paper that many times. :banghead: My movements aren't magnifying the errors disproportionately to the distance, are they (I can't think of any physics rule I'm aware of which might suggest they are)? Just doesn't make any sense to me, given the 50 and 100 yard targets...

 

[DWARREN123]

The way it sounds is the problem is you/your eye sight. If you are doing 3" groups at 100 yards then you should double that at 200 yards or maybe a little more. I would go with a larger target, say big piece of cardboard at least 3 or 4 foot square and see what is happening.
Always check the sights for correct mounting and tightness.
Let us know what you find.

 

[Swampy]

Caimlas,

Given the circumstances data that you have given us to this point.... I can see NO reason why you should not be on or near the bull @ 200 yards.

The only wild card in this equation is your eyesight and the target sizes that you are using. Trying to see that small black that you are using out at 200 yards may be your problem. You need a bigger black....

Standard bull diameter for most rifle shooting is a 6-6.5 MOA aiming black. In order to achieve the same relative size between the front post and the black at each distance you should be using targets with a 6.5" bull @ 100 and a 13" bull @ 200.

See if you can get ahold of some NRA targets. The SR target is made for 200 yards, the SR-1 for 100. Both have the correct size aiming blacks. If you can't locate any SR or SR-1's, then make them with black poster board circles glued to white cardboard.

Best,
Swampy

Garands forever

 

[Caimlas]

Updated info at bottom of original topic, fwiw.

 

[Twud]

I know this is a reach, but could your bullets be losing enough steam between 100 and 200 yds. that they're missing the target low. I understand you shot at a 24" target high, but maybe you need to aim for a point above the target.
I know it seems unlikey, but what could it hurt.
When I dial in I always start at 50 yards. This is obviously not your problem.
Wish I could offer more.

 

[Caimlas]

Think I'm going to chalk it up to environmental conditions + shooting fatigue at this point. Shooting into a strong headwind isn't fun (hell, high wind isn't fun, period), and my eyes had started to get tired. That's got to be at least part of the explanation.

 

[Dave R]

Only thing I can figure is that the wind slowed the progression of the bullet, and/or created a pressure differential which pushed the bullet up or down, resulting in a miss.

How's that sound? Plausible?

Very plausible. 25mph wind will push those .223 bullets around a lot at 200 yards.

Also, if you're like me, I have a very hard time getting a real consistent sight picture on a small bull at 200 yards. (And you said you were at the extent of your eyesight.) I have to use a bull big enough to allow me to "dot the i" consistently.

 

[Rifleman 173]

How is your eyesight? Can you CLEARLY see the sights and the target? Are you using a scope? Some vision problems, as I found out the hard way, sneak up on you. Once I hit 40 years old, every couple of years I had a new vision problem of some sort. I would suggest that you consider using a scope for testing your groups at 50, 100 and 200 yards. If you can hit with the scope, then maybe its your eyes and the metal sights. You may need new glasses or something.

 

[romma]

Any damage to your rifling inside the barrel possibly?

 

[Caimlas]

Nope, no damage to the rifle/rifling.

And, yes, my eye sight is poor, though not so poor that I can't see/distinguish the sights and the target - though targets are very "blurry" out at 200 yards for me, and need to be fairly large. IE, a 3" orange dot in the center of a 1' black target is only vaguely visible at 200 yards.

I was shooting unscoped at this range, mainly to see if I could, as I never have before. I'm pleased to see that, at least sometimes, I can shoot well enough at this range to put down a deer or similar target.

 

[Jackal]

Maybe it just wasnt your day. Maybe the thing wrong wasnt the rifle, maybe it was the shooter. I can usually go out an shoot my rifles/handguns excellently, but every once in a while, for no reason, I just plain suck. Sometimes I do one whole groups at 50 yards, other times my "groups" looks like I was checking my shotguns shot pattern. I think thats why we have the term "Hit or Miss". Keep plinking away, I always will.

 

[Swampy]

And, yes, my eye sight is poor, though not so poor that I can't see/distinguish the sights and the target - though targets are very "blurry" out at 200 yards for me, and need to be fairly large. IE, a 3" orange dot in the center of a 1' black target is only vaguely visible at 200 yards.

Caimlas,

This is normal for most iron sight shooting. The target is SUPPOSED to be blurry.... because you are trying for a hard focus on the front sight post. This is NECESSARY. If you are focusing on a sharply focused target you will have an out of focus sight post. Optical physics demands it... and with the front post out of focus, you are not going to get good groups.

I shoot Service Rifle Highpower. I am age 52. I have had bad eyes since birth... i.e. VERY myopic. That does not keep me from shooting Master Class scores at 600 yards. When I look through the sights on my M1 rifle I immediately go for a sharp focus on the post. The target is ALWAYS a fuzzy ball, regardless of size, distance, lighting or weather conditions. This is the way it should be......

I assume you are wearing glasses of some sort. If you cannot focus on the front post you need to have a set of shooting glasses made up with the prescription that will.

Best regards,
Swampy

Garands forever

 

[rangerruck]

after 100 yds, on bullets weighing less than 80 grains, wind has a absolutely horrific effect on bullets; coming off of the back of a berm the wind is blowing down, and a lot of times spinning. it could have easily been blowing down in the dirt. if you have access to this same range, when you walk out to about 150 yds, start looking for dig marks in the ground, i bet you start finding several , after that point.

 

[brian923]

i disagree with wind playing that much haveck on the rounds. i think it would take a much much stronger wind to blow a bullet, no matter what size, in to the dirt at 3000 fps. unless your shooting prone, and the bullet path is only 2" above the dirt, the whole way down to your target. but even then, you would notice gound impacts. the bullet is reaching the target in under a 1/4 second. try 150 yards, or pacs and see where its impacting. as said earlier, use a bigger target.

what twist rate is your rifle???

edit to say, i read the UPDATE of your post. didnt see it before. sorry. maybe just a bad day. ive had them.

 

[rcmodel]

+1 on two points already made.

First, a 30 MPH (44 FPS) headwind will have absolutely no effect on the 3,000+ FPS bullets trajectory.

Any rolling air coming over the berm would only have a very tiny slice of the total time-of-flight to move the bullet at all. I doubt you could even measure it.

A 30 MPH cross-wind would move the bullet about 5" sideways at 200 yards. About 12" at 300 yards.

Second, always focus on the front sight and don't worry if the target & rear sight are blurry.

That's just the way the eye has to work. If you try to focus on the target, you will not be able to see the front sight clearly at all.

The rear sight will center itself automatically without you even looking at it.

rcmodel

 

[Nhsport]

As others have said the time of flight for a 223 is so short (fast bullet) that you would have to have a huge wind to blow you completly off the 2" paper.

A great trick is to grab someone to help/watch as you shoot. if they stand behind you and you are shooting against any type of dirt or sand berm the bullet strikes will be easy for them to see. You are in recoil at the moment the bullet strikes so the shooter has a hard time seeing strikes

There are two zeros for any rifle. The line of sight (your eye looking on a straight line through the sight or optic) is a straight line and the bullet starts below it and angles up and crosses it (first or close zero) then arcs down and recrosses the line of sight (second or far zero).
With the IBZ the first zero is at the close distance (30 to 50 yards) then the bullet arcs up then crosses again at a longer distance (200 or 300 yards).
In your case the bullet might be crossing the line of sight real close (say 10 yards) then arcing down to cross the line of sight at about 75 yards which would be pretty close at both 50 and 100 yards. the arc would then steepen and be way low at 200 . My guess is that you are low.

You can get crazy thinking too hard about all the angles and arcs , best bet to save ammo is getting a buddy to spot for you . Good luck

 

[Avenger]

+1 on having somebody with you to spot the impact.

I have to note, though, that this method didn't help me get my first Mosin on paper on the 50 yard range. My spotter kept ducking the falling debris.....