Does fixed front sight position on an AR matter?

[EugenFJR]

I'll be sighting in at 25 yards on the "Z" Mark. After that I would like for the wheel marks to be accurate. Clicking to the 1 mark for 100 yards, 2 for 200, and so on. Since these are moa adjustments, I thought I might need the same sight radius as a rifle length gas system FSB for it to work out.

I just noticed this ^^^ The "z" mark is for 25 Meters (82.29 feet) The "z" was put on the A2 sights b/c when the army went from the M14 to the M16A1 the ranges were made at 25 meters to get a battle sight zero for the 1/12 twist M16A1 w/ the 55 grain bullet ( M193) When the M16A2 came out w/ the 1/7 twist barrel the proper distance would be 32 meters... So insted of changing all the ranges they added the "z" to zero at 25m, but when you go to the range, to shoot your pop up targets, you move it back down to 300. Allways use the small sight apature!!!

Distance in Meters M16A2/A4 bullet path true 300m zero
Meters Path inches
0 -2.5 ( this means the barrel is aginst the target, your sights are 2.5 inches above the bore)
25 ----- -0.33
50 ----- 1.56
100 ---- 4.37
125 ----- 5.27
150 ----- 5.8
175 ---- 5.94
200 ----- 5.68
225 ---- 4.98
250 ---- 3.82
275 ---- 2.17
300 ---- 0

Note that the bullet impacts .33 inches low at 25m This why it is necessary to raise the BDC to the "z" mark ( if you have older sights it might not have the "z" , so it would be 8/3 plus 1 click) Then return the sights to 8/3 for qualification or Battle

**** You do not have to do this for the M4 rifle just the A2/A4 rifle

 

[freedom]

I just noticed this ^^^ The "z" mark is for 25 Meters (82.29 feet) The "z" was put on the A2 sights b/c when the army went from the M14 to the M16A1 the ranges were made at 25 meters to get a battle sight zero for the 1/12 twist M16A1 w/ the 55 grain bullet ( M193) When the M16A2 came out w/ the 1/7 twist barrel the proper distance would be 32 meters... So insted of changing all the ranges they added the "z" to zero at 25m, but when you go to the range, to shoot your pop up targets, you move it back down to 300. Allways use the small sight apature!!!

Distance in Meters M16A2/A4 bullet path true 300m zero
Meters Path inches
0 -2.5 ( this means the barrel is aginst the target, your sights are 2.5 inches above the bore)
25 ----- -0.33
50 ----- 1.56
100 ---- 4.37
125 ----- 5.27
150 ----- 5.8
175 ---- 5.94
200 ----- 5.68
225 ---- 4.98
250 ---- 3.82
275 ---- 2.17
300 ---- 0

Note that the bullet impacts .33 inches low at 25m This why it is necessary to raise the BDC to the "z" mark ( if you have older sights it might not have the "z" , so it would be 8/3 plus 1 click) Then return the sights to 8/3 for qualification or Battle

**** You do not have to do this for the M4 rifle just the A2/A4 rifle

Excellent post. I am going to get my initial zero shooting at a 1" square. That means I should want my POI not in the center, but just above the low side of the target, POA dead center?

 

[DarthVader]

Excellent post. I am going to get my initial zero shooting at a 1" square. That means I should want my POI not in the center, but just above the low side of the target, POA dead center?

Or, you could aim for the bottom edge and look for POI to be just under the line

 

[freedom]

Or, you could aim for the bottom edge and look for POI to be just under the line

I normally shoot 6 o'clock hold, but that's only optimal for fixed sized targets at fixed distances, at least in my understanding. With shooting from 1-600 yards wouldn't it be better for center hold? 6 o'clock is better for my eyes, but I don't want to worry about adjusting my hold for different distances.

 

[EugenFJR]

Excellent post. I am going to get my initial zero shooting at a 1" square. That means I should want my POI not in the center, but just above the low side of the target, POA dead center?

Are you useing a 20 inch barreled rifle? Or a 16 inch? And I have a shit load of army 25 meter targets, when is your class, and when are you going to the range to get your zero?

 

[DarthVader]

I normally shoot 6 o'clock hold, but that's only optimal for fixed sized targets at fixed distances, at least in my understanding. With shooting from 1-600 yards wouldn't it be better for center hold? 6 o'clock is better for my eyes, but I don't want to worry about adjusting my hold for different distances.

Yes. I was just thinking about the initial 25 yd zero. But it really doesn't matter once you verify at distance. Center hold is what you'd ultimately use anyway.

 

[freedom]

http://www.bjonessights.com/AR15.html

Thinking about purchasing this with the 1/4 moa screw. I can qualify on scaled targets at 25m with irons, but so far I'm a little short at actual distance.

Probably a software issue, I need to dry fire more. That's a lie, I need to dry fire.

 

[EugenFJR]

Yes. I was just thinking about the initial 25 yd zero. But it really doesn't matter once you verify at distance. Center hold is what you'd ultimately use anyway.

I agree, I always hold center mass... Unless I'm shooting a M240B, or M249 or 50 cal HBMG....

 

[freedom]

Are you useing a 20 inch barreled rifle? Or a 16 inch? And I have a shit load of army 25 meter targets, when is your class, and when are you going to the range to get your zero?

Right now, I'm planning on 20". I'm putting together a 16" too. I have others, but the carbine length or mid length sight radius isn't enough for me, I'm looking for every legal advantage.

I have some copies of these, https://www.bing.com/images/search?...orm=QBIDMH&pq=appleseed+aqt&sc=0-11&sp=-1&sk=, that's what we use to teach the 25m classes. I also have some https://www.bing.com/images/search?...orm=QBIR&pq=army+50m+targets&sc=0-7&sp=-1&sk=. I'm trying to make the range Saturday, and the next KD is the end of January at the CMP in Alabama.

 

[EugenFJR]

The bottom 4 squares ( just over 300 meters) Is where I like zero (POI), but point of aim is always center mass.

 

[freedom]

View attachment 11217

The bottom 4 squares ( just over 300 meters) Is where I like zero (POI), but point of aim is always center mass.

I think I have some of those.

 

[freedom]

I'd go if you want to take me... I got spoiled at Ft. McCoy, get your rifle zeroed, go shoot it to 300m, or go to range 34, and depending what you had, stretch it out to 1200m meters... But I will say this my eyes have gotten bad, and need to find a Bob Jones sight if I'm going to shoot irons... If I dont wear glasses, front sight is clear, cant see the target... If I wear glasses, I can see the target, front sight is fuzzy... Sucks to be old...

I just ordered a Bob Jones aperture/sight and his match kit to have 1/4 moa adjustments. In for $101 shipped, but it'll be worth it to clear a target with irons at 600.

 

[Hayata]

I just noticed this ^^^ The "z" mark is for 25 Meters (82.29 feet) The "z" was put on the A2 sights b/c when the army went from the M14 to the M16A1 the ranges were made at 25 meters to get a battle sight zero for the 1/12 twist M16A1 w/ the 55 grain bullet ( M193) When the M16A2 came out w/ the 1/7 twist barrel the proper distance would be 32 meters... So insted of changing all the ranges they added the "z" to zero at 25m, but when you go to the range, to shoot your pop up targets, you move it back down to 300. Allways use the small sight apature!!!

Distance in Meters M16A2/A4 bullet path true 300m zero
Meters Path inches
0 -2.5 ( this means the barrel is aginst the target, your sights are 2.5 inches above the bore)
25 ----- -0.33
50 ----- 1.56
100 ---- 4.37
125 ----- 5.27
150 ----- 5.8
175 ---- 5.94
200 ----- 5.68
225 ---- 4.98
250 ---- 3.82
275 ---- 2.17
300 ---- 0

Note that the bullet impacts .33 inches low at 25m This why it is necessary to raise the BDC to the "z" mark ( if you have older sights it might not have the "z" , so it would be 8/3 plus 1 click) Then return the sights to 8/3 for qualification or Battle

**** You do not have to do this for the M4 rifle just the A2/A4 rifle

And THIS explains why I had such a hard time with the 175 yd pop up!

 

[freedom]

Took the rifle out today even though I've got a new rear aperture ordered. The good news is I sighted in at 25 meters on the Z. Went out to 100, shot on the 6/3 mark and came in high like I'm supposed to. Dialed down 3 clicks from the 6/3 and was dead on (a couple nice 2 or 2+" groups). I think 3 clicks is the "right" adjustment.

The bad. I almost unscrewed the front sight post. There is a gap between the body of the sight and the round base of the post. It's marked YHM, but other than that I don't know anything. It also seems to have 1/2min adjustments instead of the 1moa I was expecting. It is still caught by the detent. Is this a problem?

 

[DarthVader]

Not sure what height post they use. You just need to order a replacement "tall" post

 

[freedom]

Not sure what height post they use. You just need to order a replacement "tall" post

I was probably going to do this anyway. The post is 7moa wide, I probably want to replace it with a 4moa post.

 

[freedom]

 

[freedom]

Not sure what height post they use. You just need to order a replacement "tall" post

This seems to be what I have

http://www.midwayusa.com/Product/62...t-sight-gas-block-height-ar-15-aluminum-matte

It says it's for a railed gas block, could that be the problem?

 

[DarthVader]

This seems to be what I have

http://www.midwayusa.com/Product/62...t-sight-gas-block-height-ar-15-aluminum-matte

It says it's for a railed gas block, could that be the problem?

Probably so.

 

[DarthVader]

I was probably going to do this anyway. The post is 7moa wide, I probably want to replace it with a 4moa post.

The National Match post?