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Posted: 11/19/2008 5:15:47 PM EDT
I went to the range today, my DPMS Panther Lite 16A1, I have my sights zeroed at 100 yards, and was shooting at 25 yards today, at an indoor range. What has me all fucked up, is that all of my rounds were hitting 1-3 inches low, NOT HIGH. WTF?????? Even when I flipped the sight, my POI only moved up 1 inch. WTF??????????????

I will admit, my training is with A2 sights, A3 BUIS, and M68 Aimpoint, so I am not too terribly familiar with the A1. What I am wondering is why the POI is lower at close range, rather than Higher.

Also, what is the difference between the 2 sights on the A1 setup? I am assuming that the second sight either raises or lowers POI, and after my shooting today, I am guessing it raises it, but by how much, and at what Range?

Just one more reason why I am planning on putting in an A3 flat top.


Thanks guys
Link Posted: 11/19/2008 5:17:11 PM EDT
Hmm....









Get a tritium sight post!
Link Posted: 11/19/2008 5:19:35 PM EDT
Originally Posted By gonzo_beyondo:
Hmm....









Get a tritium sight post!


Well, I shoot 40/40 every time at the range, m16, or m4, A2, A3, or Aimpoint.

I have been thinking of getting the tritium post, just to aid visibility.....
but why do YOU suggest it?

Link Posted: 11/19/2008 5:19:47 PM EDT
[Last Edit: 11/19/2008 5:21:55 PM EDT by JoeCoastie]
Shoot at a standard 1000 inch target from 1000 inches away. it's like 27 yrds 2 feet and some change off the top of my head. If you zero on that, you should be dead center at 100 yards....at least, that's how I zero my A2. Yes, I know your question is for an A1 but methinks it shouldn't matter.

ETA: are you talking about the rear aperature? As in big hole small hole? If so, the big one is for "Combat distances" 0-200 I believe. I could be wrong and the small aperature is for more fine tuned work at greater distance out to say 540 yds or so.
Link Posted: 11/19/2008 5:21:46 PM EDT
[Last Edit: 11/19/2008 5:25:16 PM EDT by RealFastV6]
Because the sights are on top of the barrel.

It's always going to shoot low up close. Doesn't matter if it's A1, A2, Aimpoint, Acog, Eothing, Tacpoint, AK47...
Link Posted: 11/19/2008 5:24:20 PM EDT
[Last Edit: 11/19/2008 5:53:35 PM EDT by tommytrauma]
Originally Posted By natethreet:
I went to the range today, my DPMS Panther Lite 16A1, I have my sights zeroed at 100 yards, and was shooting at 25 yards today, at an indoor range. What has me all fucked up, is that all of my rounds were hitting 1-3 inches low, NOT HIGH. WTF?????? Even when I flipped the sight, my POI only moved up 1 inch. WTF??????????????

I will admit, my training is with A2 sights, A3 BUIS, and M68 Aimpoint, so I am not too terribly familiar with the A1. What I am wondering is why the POI is lower at close range, rather than Higher.

Also, what is the difference between the 2 sights on the A1 setup? I am assuming that the second sight either raises or lowers POI, and after my shooting today, I am guessing it raises it, but by how much, and at what Range?

Just one more reason why I am planning on putting in an A3 flat top.


Thanks guys


Think it through. You're zeroed so POA and POI are the same at 100 yards, ie your round rises to intersect the sight plane at that distance. Your sights sit a couple inches above the bore. Closer then 100, your hits will be low. Either your A2 sights did the same thing, or you were holding the rifle upside down.

As you know though, a 100 yard zero will give you ~4" or less difference between POA and POI out to somewhere around 250 yards.

Link Posted: 11/19/2008 5:33:21 PM EDT
What was already said is correct. The sights are about 3" above the center of the bore. So you are 3" low at the muzzle. Also "line of sight" is a straight line. Bullet path is an arc. Starts out 3" low by about 60-80 yards it is right on. at about 125 yards it may be a little high. By 200 yards or so it will be low again.
Link Posted: 11/19/2008 5:37:00 PM EDT
With a 100 Yard Zero with that rifle, you should impact 1.5" low at 25 yards. That rifle was originally designed to have a BSZ of 250 meters, if I recall. When you flipped the sight it changed the zero to 350 meters?

With my ballistic software, and by your statement that the impact raised 1 inch, I think that when you flip your sight you will have approximately a 300 yard zero.

Link Posted: 11/19/2008 5:39:24 PM EDT
As stated above, it doesn't matter what sights you have, they are above the bore so the closer you get the lower you shoot.

Put your sights on a target with the muzzle against your target as well. Are you going to hit where the sights are or where the muzzle is?

That is why it is called a 100 yard zero, and not just a zero. At a 100 yard zero, you should also be good at about 400 yards since the path of the projectile is going in an upward direction and will fall back down to the same height at 400 yards as it was at 100 yards.
Link Posted: 11/19/2008 5:39:59 PM EDT
tag
Link Posted: 11/19/2008 5:40:58 PM EDT
Originally Posted By RealFastV6:
Because the sights are on top of the barrel.

It's always going to shoot low up close. Doesn't matter if it's A1, A2, Aimpoint, Acog, Eothing, Tacpoint, AK47...


This.
Link Posted: 11/19/2008 5:40:58 PM EDT
Originally Posted By JoeCoastie:
Shoot at a standard 1000 inch target from 1000 inches away. it's like 27 yrds 2 feet and some change off the top of my head. If you zero on that, you should be dead center at 100 yards....at least, that's how I zero my A2. Yes, I know your question is for an A1 but methinks it shouldn't matter.

ETA: are you talking about the rear aperature? As in big hole small hole? If so, the big one is for "Combat distances" 0-200 I believe. I could be wrong and the small aperature is for more fine tuned work at greater distance out to say 540 yds or so.


With A1, the rear aperatures are the same diameter, as far as I can tell, they are just different elevations.
Link Posted: 11/19/2008 5:41:06 PM EDT
Originally Posted By RealFastV6:
Because the sights are on top of the barrel.

It's always going to shoot low up close. Doesn't matter if it's A1, A2, Aimpoint, Acog, Eothing, Tacpoint, AK47...


this

the bullet is dropping, but the line of sight and line of muzzle are are two diff spots
Link Posted: 11/19/2008 5:44:21 PM EDT
Originally Posted By natethreet:

Just one more reason why I am planning on putting in an A3 flat top.



OK...but avoid the magic bullet. Merely adding optical sights on an A3 won't compensate for what you are observing. The previous posters got it right. Learn those irons...and they will not fail you.
Link Posted: 11/19/2008 5:47:27 PM EDT
Originally Posted By v-dawg:
As stated above, it doesn't matter what sights you have, they are above the bore so the closer you get the lower you shoot.

Put your sights on a target with the muzzle against your target as well. Are you going to hit where the sights are or where the muzzle is?

That is why it is called a 100 yard zero, and not just a zero. At a 100 yard zero, you should also be good at about 400 yards since the path of the projectile is going in an upward direction and will fall back down to the same height at 400 yards as it was at 100 yards.


???

With a 100 yard zero, the projectile crosses the line sight for the first time at 100 yards. It achieves its max ord at about 108, and then crosses back on its way down at about 112 yards.

At 400 yards, the bullet will be about 26" low. For your statement to be true, the bullet would have to be travelling at over 6000 feet per second.
Link Posted: 11/19/2008 5:49:21 PM EDT
Originally Posted By natethreet:
Originally Posted By gonzo_beyondo:
Hmm....









Get a tritium sight post!


Well, I shoot 40/40 every time at the range, m16, or m4, A2, A3, or Aimpoint.

I have been thinking of getting the tritium post, just to aid visibility.....
but why do YOU suggest it?



Aww man, I knew it was a poor joke.

Often people will buy the latest tacticool accessories or upgrades to fix problems that aren't really problems.
I was just pullin' your leg.
Link Posted: 11/19/2008 5:52:04 PM EDT
Originally Posted By Epraslick:
Originally Posted By v-dawg:
As stated above, it doesn't matter what sights you have, they are above the bore so the closer you get the lower you shoot.

Put your sights on a target with the muzzle against your target as well. Are you going to hit where the sights are or where the muzzle is?

That is why it is called a 100 yard zero, and not just a zero. At a 100 yard zero, you should also be good at about 400 yards since the path of the projectile is going in an upward direction and will fall back down to the same height at 400 yards as it was at 100 yards.


???

With a 100 yard zero, the projectile crosses the line sight for the first time at 100 yards. It achieves its max ord at about 108, and then crosses back on its way down at about 112 yards.

At 400 yards, the bullet will be about 26" low. For your statement to be true, the bullet would have to be travelling at over 6000 feet per second.


What he said.

Link Posted: 11/19/2008 5:53:07 PM EDT
Originally Posted By Epraslick:
With a 100 Yard Zero with that rifle, you should impact 1.5" low at 25 yards. That rifle was originally designed to have a BSZ of 250 meters, if I recall. When you flipped the sight it changed the zero to 350 meters?

With my ballistic software, and by your statement that the impact raised 1 inch, I think that when you flip your sight you will have approximately a 300 yard zero.



250 then 375 meters on the L marked original.

I changed to a same plane rear with large ghost ring and zeroed at 50/200, done.
Link Posted: 11/19/2008 5:55:51 PM EDT
Originally Posted By AmericanPatriot:
Originally Posted By Epraslick:
With a 100 Yard Zero with that rifle, you should impact 1.5" low at 25 yards. That rifle was originally designed to have a BSZ of 250 meters, if I recall. When you flipped the sight it changed the zero to 350 meters?

With my ballistic software, and by your statement that the impact raised 1 inch, I think that when you flip your sight you will have approximately a 300 yard zero.



250 then 375 meters on the L marked original.

I changed to a same plane rear with large ghost ring and zeroed at 50/200, done.


I went with the Ashley same plane at 100. Pretty much same difference. Then I bought an Aimpoint. I'm realy glad I mastered my irons first, 'cause I can see how a red dot could become a hell of a crutch.

Link Posted: 11/19/2008 5:58:01 PM EDT
Zero thet sucker at 250 meters. That's what we did with the A1 and A2 when I was in.
Make it easy and make or get a 25mzero target. Put the rounds in a circle about the size of a silver dollar at 25M and it will be zeroed in at 250 meters. That would be assuming that you are using military equivilant ammo.
Link Posted: 11/19/2008 6:02:54 PM EDT
[Last Edit: 11/19/2008 6:04:14 PM EDT by tommytrauma]
Originally Posted By hobbsar:
Zero thet sucker at 250 meters. That's what we did with the A1 and A2 when I was in.
Make it easy and make or get a 25mzero target. Put the rounds in a circle about the size of a silver dollar at 25M and it will be zeroed in at 250 meters. That would be assuming that you are using military equivilant ammo.


Do a search on the Santose zero or improved battlesight zero. Or take a look at the chart I've already posted twice.
Link Posted: 11/19/2008 6:03:32 PM EDT
That's really good that you can see the utility and logic behind learning irons, first.

I do a lot of marksmanship training, from combat service support to elements of SOF, and it boggles my mind that some people (no matter how experienced) cannot see this simple truth. They think that, "I will always have my optic!." What they fail to realize is that learning fundamentals, such as sight alignment and the use of iron sights, applies to not just your personal weapon when te optics fail, but to pistols, machine guns, and any weapon they might find in their hands.

Technology is awesome, but we shouldn't lose sight of mastering the basic skills of marksmanship.
Link Posted: 11/19/2008 6:11:59 PM EDT
Crank the front sight post down to bring the muzzle up, you probably turned the front sight post the wrong way and actually made it taller.

The front sight post may not be standard height on it and may be longer than normal.

I didn't have this problem with my Colt Sp-1, But i zeroed for 50 yards to give me a flater tragectory out to the effective range of the round.
Link Posted: 11/19/2008 6:15:05 PM EDT
[Last Edit: 11/19/2008 6:18:05 PM EDT by v-dawg]
Originally Posted By Epraslick:
Originally Posted By v-dawg:
As stated above, it doesn't matter what sights you have, they are above the bore so the closer you get the lower you shoot.

Put your sights on a target with the muzzle against your target as well. Are you going to hit where the sights are or where the muzzle is?

That is why it is called a 100 yard zero, and not just a zero. At a 100 yard zero, you should also be good at about 400 yards since the path of the projectile is going in an upward direction and will fall back down to the same height at 400 yards as it was at 100 yards.


???

With a 100 yard zero, the projectile crosses the line sight for the first time at 100 yards. It achieves its max ord at about 108, and then crosses back on its way down at about 112 yards.

At 400 yards, the bullet will be about 26" low. For your statement to be true, the bullet would have to be travelling at over 6000 feet per second.


My bad! I guess it helps that I have a supertacticalshortbarrelAR that propels the bullet at about 10,000 miles per second.

I used bad math and assumed that since I have heard a 50 yard zero is about a 200 yard zero that it would equate 100 to 400.

edit to add:
I am zero'd at 50. With targets we train on, as you approach the target, aiming at the hairline of the suspect puts the impact right about between the eyes around 10 yards.



Link Posted: 11/19/2008 6:15:26 PM EDT
Crank the front sight post down to bring the muzzle up, you probably turned the front sight post the wrong way and actually made it taller.

The front sight post may not be standard height on it and may be longer than normal.

I didn't have this problem with my Colt Sp-1, But i zeroed for 50 yards to give me a flater tragectory out to the effective range of the round.
Link Posted: 11/19/2008 6:17:40 PM EDT
Originally Posted By tommytrauma:
Originally Posted By hobbsar:
Zero thet sucker at 250 meters. That's what we did with the A1 and A2 when I was in.
Make it easy and make or get a 25mzero target. Put the rounds in a circle about the size of a silver dollar at 25M and it will be zeroed in at 250 meters. That would be assuming that you are using military equivilant ammo.


Do a search on the Santose zero or improved battlesight zero. Or take a look at the chart I've already posted twice.


IMO, the optimum zero for the M16/M4 family of weapons is a 250 Meter zero. You are no more than about 4" from POI out to 300 Meters, and it preserves the functionality of the BDC. If you zero low in the 4 cm circle, you are achieving close to a 250 Meter zero.
Link Posted: 11/19/2008 6:44:50 PM EDT
Originally Posted By Epraslick:
Originally Posted By tommytrauma:
Originally Posted By hobbsar:
Zero thet sucker at 250 meters. That's what we did with the A1 and A2 when I was in.
Make it easy and make or get a 25mzero target. Put the rounds in a circle about the size of a silver dollar at 25M and it will be zeroed in at 250 meters. That would be assuming that you are using military equivilant ammo.


Do a search on the Santose zero or improved battlesight zero. Or take a look at the chart I've already posted twice.


IMO, the optimum zero for the M16/M4 family of weapons is a 250 Meter zero. You are no more than about 4" from POI out to 300 Meters, and it preserves the functionality of the BDC. If you zero low in the 4 cm circle, you are achieving close to a 250 Meter zero.


I'd understood that a 25 meter zero and 250 were effectively the same. not correct?
Link Posted: 11/19/2008 6:48:57 PM EDT
that's what I thought, i was just fubar'd in my numbers
Link Posted: 11/19/2008 7:08:33 PM EDT
Sight hold over is a bitch in 3-gun matches when you are often engaging targets at bayonet distance. Especially when there are no-shoots involved at these distances.

Sights, like A1's and A2's sighted in at any usable distance will require user compensation at closer range due to the difference between bore and line-of-sight.
Link Posted: 11/19/2008 7:20:22 PM EDT
[Last Edit: 11/19/2008 7:30:44 PM EDT by Epraslick]
A true 25 meter POI zero with an M4 (62 gr. bullet@2850 fps) will yield a 300 meter zero.

With an M16 (20" barrel=3050 fps) you will get a 338 meter zero.

If you want a 250 meter zero at short range you need to zero at approx. 33 meters with an M4, and 37 meters with an M16.

That's the real problem with trying to do it this way, any small error at close range will drastically affect the final zero. It's the same reason why 25M zeroing (with adjusting the BDC on the M16 to "cheat" the POI) is LEAST desirable option. ALWAYS zero at distance.


NOTE: This data is for the M855, 62 gr. round. The OP referenced 55 gr. ammo, I think.
Link Posted: 11/19/2008 7:22:16 PM EDT
Seriously?

If your A1 or A2 or aimpoint or eotech or whatever is zeroed for 100 yards they will all, ALL shoot low at 25 yards.

Link Posted: 11/19/2008 7:28:38 PM EDT
Originally Posted By tommytrauma:
Originally Posted By hobbsar:
Zero thet sucker at 250 meters. That's what we did with the A1 and A2 when I was in.
Make it easy and make or get a 25mzero target. Put the rounds in a circle about the size of a silver dollar at 25M and it will be zeroed in at 250 meters. That would be assuming that you are using military equivilant ammo.


Do a search on the Santose zero or improved battlesight zero. Or take a look at the chart I've already posted twice.


Just telling you what worked 20 years ago with the A1 and what worked six months ago with my own DPMS Panther Arms 16 Lite. No need to get testy.

Link Posted: 11/19/2008 7:34:05 PM EDT
Originally Posted By tommytrauma:
Originally Posted By Epraslick:
Originally Posted By tommytrauma:
Originally Posted By hobbsar:
Zero thet sucker at 250 meters. That's what we did with the A1 and A2 when I was in.
Make it easy and make or get a 25mzero target. Put the rounds in a circle about the size of a silver dollar at 25M and it will be zeroed in at 250 meters. That would be assuming that you are using military equivilant ammo.


Do a search on the Santose zero or improved battlesight zero. Or take a look at the chart I've already posted twice.


IMO, the optimum zero for the M16/M4 family of weapons is a 250 Meter zero. You are no more than about 4" from POI out to 300 Meters, and it preserves the functionality of the BDC. If you zero low in the 4 cm circle, you are achieving close to a 250 Meter zero.


I'd understood that a 25 meter zero and 250 were effectively the same. not correct?


That's how we did it and I always shot Expert. Funny thing is that th eonly target I had problems with was the 250 meter target. Go figure.
Link Posted: 11/19/2008 7:40:40 PM EDT
[Last Edit: 11/20/2008 11:47:06 AM EDT by TheKill]
I do believe my M16A1 and M16A2 Marksmanship training FM 23-9 says 25/250 for A1 with M193. Maybe I'll dig it out.


ETA: As everyone else has noted, the sights on the AR/M platform are significantly higher than the bore, so the closer you get, the lower you hit inside your initial zero range.
Link Posted: 11/19/2008 7:59:26 PM EDT
Originally Posted By TheKill:
I do believe my M16A1 and M16A2 Marksmanship training FM 23-9 says 25/250 for A1 with M193. Maybe I'll dig it out.


ETA: If you can see the whites of their eyes, I aim at the center of forehead to get T zone hits. As everyone else has noted, the sights on the AR/M platform are significantly higher than the bore, so the closer you get, the lower you hit inside your initial zero range.


With M193 (55 gr. ammo@3250 fps) that is correct. 25M zero=250M zero. Not the same with M855 ammo.
Link Posted: 11/20/2008 6:19:01 AM EDT
Originally Posted By natethreet:
I went to the range today, my DPMS Panther Lite 16A1, I have my sights zeroed at 100 yards, and was shooting at 25 yards today, at an indoor range. What has me all fucked up, is that all of my rounds were hitting 1-3 inches low, NOT HIGH. WTF?????? Even when I flipped the sight, my POI only moved up 1 inch. WTF??????????????



Your rounds are hitting exactly where they should hit at 25 yds. The sights are above the bore. Your rifle is sighted in correctly.

Link Posted: 11/20/2008 6:48:49 AM EDT
[Last Edit: 11/20/2008 7:17:11 AM EDT by jhud]
Ive always though the A1 sight was relatively easy. In fact I prefer it. The A2 dial mess simply conused the hell out of me. Its also difficult to use that big honking aperture hole shooting long range.

WAIT. My A1 aperture isnt marked. It is simply installed to that the peeps are concaved from the front. I never flip it. It is set at 50 yards and hits up to the distances I shoot. I guess I need to flip that baby and see how the POI moves. This is on a 16" carbine

I prefer the XS same plane aperture on a A1 rec. Works good on a SBR. Zero's at 50 of course, using the small hole.
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