AR15.Com Archives
 Why are AR-15 sights so high above the bore?
widerstehe  [Member]
2/22/2011 8:04:57 PM
It's a couple inches or so, right? I mean, forget about the carry handle for a moment. Even flat top uppers come with the front sight post so high up. Wouldn't the gun benefit from having low profile sights? I was thinking about this after seeing the Benelli MR1, which I don't like, but I do like the sights better than the AR.
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skinnysarge79  [Team Member]
2/22/2011 8:06:35 PM
Buffer tube keeps you from aligning your eye right above the barrel. It acts like a high comb.
Postal0311  [Life Member]
2/22/2011 8:07:22 PM
Look at the position of the buffer tube.

You are limited on how low you can go with sights, and still comfortably use them.
SevenMMmag  [Member]
2/22/2011 8:08:13 PM
Originally Posted By widerstehe:
It's a couple inches or so, right? I mean, forget about the carry handle for a moment. Even flat top uppers come with the front sight post so high up. Wouldn't the gun benefit from having low profile sights? I was thinking about this after seeing the Benelli MR1, which I don't like, but I do like the sights better than the AR.


because of the straight line profile of the AR, the sights need to be higher in order for you to get a proper cheek weld
KRONIIK  [Member]
2/22/2011 8:08:14 PM
The buffer tube inside the stock requires that the stock have an unusually high comb.
The sights are high enough to be able to see through them.

Most shooters would be unable to get their head low enough if conventional iron sights were used.


Edited to add:
I hereby officially give up on attempting to give the first correct answer to an OP.
Combat_Jack  [Team Member]
2/22/2011 8:08:22 PM
So, how do you propose you would get your head low enough to see the sights?
operatorerror  [Team Member]
2/22/2011 8:10:51 PM

Originally Posted By Combat_Jack:
So, how do you propose you would get your head low enough to see the sights?

A bolt and buffer system like the FAL would work. But I'm sure there's a reason why it wasn't used.
widerstehe  [Member]
2/22/2011 8:12:14 PM
Originally Posted By Combat_Jack:
So, how do you propose you would get your head low enough to see the sights?


I really don't know. My original question has been answered, I didn't realize this was the reason for the high sights.
VBC  [Team Member]
2/22/2011 8:13:04 PM
The straight buffer tube requiring the higher sights is actually beneficial for a battle rifle because higher sights will increase the maximum point blank range, or in other words, allows the implementation of an "improved battle sight" type of zeroing.

Rem700PSS  [Team Member]
2/22/2011 8:13:13 PM
Just poor design

Combat_Jack  [Team Member]
2/22/2011 8:16:19 PM
The AR was designed with a bolt carrier group that essentially floats in the upper receiver. The gas impulse is on-axis; that is to say that it pushes the bolt forward and out of the carrier, and which helps to push the carrier to the rear.

Because of this design, there is no need for receiver rails made of steel, which both makes the design cheaper and lighter.

The FAL is a great rifle, but it lacks the utterly simple design of the AR.

If you want to mount sights to the barrel you are going to have to make some compromises.
kap_x  [Team Member]
2/22/2011 8:16:32 PM
Apart from the reasons mentioned in the post directly above me, the design of the AR-15 is brilliant in that the barrel, bolt, bolt carrier, and buffer are all along the same axis. This means that the recoil impulse is driven straight back against the body, instead of causing the weapon to "cam" or rotate along a decentralized axis.
This is one of the main contributors to the AR-15's low recoil characteristics, and thus faster follow-up shots and higher levels of accuracy in rapid fire.

However, in doing so, the sight had to be raised so the shooter could still acquire a suitable cheekweld on the weapon. The trajectory of the cartridge, and the modern zeros help off-set the impact of having such high sight height over bore, since the bullet will fly flat through most of its effective or used range.
Combat_Jack  [Team Member]
2/22/2011 8:16:51 PM
Originally Posted By VBC:
The straight buffer tube requiring the higher sights is actually beneficial for a battle rifle because higher sights will increase the maximum point blank range, or in other words, allows the implementation of an "improved battle sight" type of zeroing.



And this.
webtaz99  [Team Member]
2/22/2011 8:17:40 PM
Design = compromise.

A bore in line with the shoulder helps the user handle recoil, but the eyes have trouble getting there.

A bore in line with a comfortable sight picture makes recoil more of a problem, even though it's easy on the eyes.
novaDAK  [Team Member]
2/22/2011 8:19:06 PM


not unique to the AR15.
ColonelHurtz  [Team Member]
2/22/2011 8:20:00 PM
The sights aren't high, the bore is low.
Straight line design.
Vulture774  [Member]
2/22/2011 8:22:55 PM
<mini-hijack>

OK...What stock/adjustable cheek would be best on an A2 config when using a scope that mounts to the carry handle? (Barska)

</mini-hijack> <sorry OP, just curious....>


762wolverine  [Team Member]
2/22/2011 8:27:00 PM
I always thought it was designed that way so that you could use a gas mask and still use the sights.


just a guess on my part.
Mal_means_bad  [Member]
2/22/2011 8:27:27 PM
Also note the location of the charging handle on the first AR15's:


The "carry handle" was never meant for carrying, it's a protective structure around a charging handle that is no longer there, similar to the FAMAS.

I'm sure you could work out the recoil mechanism to drop the cheek weld some, but the first AR's also had a CH in the way, between the two it was best to leave well enough alone.
kap_x  [Team Member]
2/22/2011 8:28:59 PM

Originally Posted By Mal_means_bad:
Also note the location of the charging handle on the first AR15's:
http://t1.gstatic.com/images?q=tbn:ANd9GcQBvAlo-lyxY8Q_dM_l_GCC7xhpxfBOP3HJ9wQstBs3o5b3LKhXLA&t=1

The "carry handle" was never meant for carrying, it's a protective structure around a charging handle that is no longer there, similar to the FAMAS.

I'm sure you could work out the recoil mechanism to drop the cheek weld some, but the first AR's also had a CH in the way, between the two it was best to leave well enough alone.

Excellent point!
Badger66  [Team Member]
2/22/2011 8:41:17 PM
Originally Posted By kap_x:

Originally Posted By Mal_means_bad:
Also note the location of the charging handle on the first AR15's:
http://t1.gstatic.com/images?q=tbn:ANd9GcQBvAlo-lyxY8Q_dM_l_GCC7xhpxfBOP3HJ9wQstBs3o5b3LKhXLA&t=1

The "carry handle" was never meant for carrying, it's a protective structure around a charging handle that is no longer there, similar to the FAMAS.

I'm sure you could work out the recoil mechanism to drop the cheek weld some, but the first AR's also had a CH in the way, between the two it was best to leave well enough alone.

Excellent point!


Looks like you can reach the bolt catch when you pull back the charging handle without having to take your hand off the pistol grip! Stoner had it worked out after all.
AFSOC  [Team Member]
2/22/2011 8:41:39 PM
I'll just leave this here....

Keith_J  [Team Member]
2/22/2011 8:48:51 PM
Muzzle climb reduction. Yes, it also helps extend the point blank range, this is incidental but worthy.

The M14 was unusable in full auto. The AR10 more so.

Sullivan just scaled down the AR10 to make the AR15.
Pokernut  [Member]
2/22/2011 8:53:04 PM
was never in the military but i have it on good authority that if you get caught carryng youre rifle by the carry handle in boot thats your ass and your getting smoked.
Frank_Castle  [Member]
2/22/2011 8:55:28 PM
Originally Posted By widerstehe:
It's a couple inches or so, right? I mean, forget about the carry handle for a moment. Even flat top uppers come with the front sight post so high up. Wouldn't the gun benefit from having low profile sights? I was thinking about this after seeing the Benelli MR1, which I don't like, but I do like the sights better than the AR.


It was explained to me (during BRM) that the barrel is actually slightly tilted upward and thus the bullet arcs. The point of aim matches at 25 meters and 300 meters.
I have the latest FM on the M16/M4 and it mentions that somewhere in the technical section also.
JBlitzen  [Team Member]
2/22/2011 8:56:00 PM
Originally Posted By SevenMMmag:
Originally Posted By widerstehe:
It's a couple inches or so, right? I mean, forget about the carry handle for a moment. Even flat top uppers come with the front sight post so high up. Wouldn't the gun benefit from having low profile sights? I was thinking about this after seeing the Benelli MR1, which I don't like, but I do like the sights better than the AR.

because of the straight line profile of the AR, the sights need to be higher in order for you to get a proper cheek weld

This.



Notice how your cheek rests below the line of the barrel.

Compare that with this:



Notice how your cheek is above the line of the barrel. That's where the extra inch or two of sight offset comes from.
DonS  [Member]
2/22/2011 8:57:15 PM
Originally Posted By kap_x:
Apart from the reasons mentioned in the post directly above me, the design of the AR-15 is brilliant in that the barrel, bolt, bolt carrier, and buffer are all along the same axis. This means that the recoil impulse is driven straight back against the body, instead of causing the weapon to "cam" or rotate along a decentralized axis.
This is one of the main contributors to the AR-15's low recoil characteristics, and thus faster follow-up shots and higher levels of accuracy in rapid fire.

However, in doing so, the sight had to be raised so the shooter could still acquire a suitable cheekweld on the weapon. The trajectory of the cartridge, and the modern zeros help off-set the impact of having such high sight height over bore, since the bullet will fly flat through most of its effective or used range.


This is also the reason for the pistol grip.
Keith_J  [Team Member]
2/22/2011 9:00:13 PM

Originally Posted By Pokernut:
was never in the military but i have it on good authority that if you get caught carryng youre rifle by the carry handle in boot thats your ass and your getting smoked.

Never with the A1 or A2.
SpacemanSpiff  [Member]
2/22/2011 9:01:56 PM
Originally Posted By Rem700PSS:
Just poor design





I don't think I have ever seen you post anything that would cause me to believe you are over the age of twelve.
Mach  [Team Member]
2/22/2011 9:06:08 PM
Originally Posted By novaDAK:
http://www.proxibid.com/AuctionImages/4103/31795/Detail/405.jpg

not unique to the AR15.


What?

The piston, BCG are not in line with the bore on the AK, they sit above it and add to the muzzle rise during fire. It is completely different than what is talked about in this thread

ETA And the BCG does not extend into the stock which is why the stock on the AK is bent down so a good cheek weld can be used with the sights very close to the bore.
DanTSX  [Team Member]
2/22/2011 9:07:47 PM
It is amazing just how much awesome info, yet how much crap info has come up in only one page of this thread!


The good info has been REALLY good. The bad info has been really
SpacemanSpiff  [Member]
2/22/2011 9:09:03 PM
Originally Posted By Mach:
Originally Posted By novaDAK:
http://www.proxibid.com/AuctionImages/4103/31795/Detail/405.jpg

not unique to the AR15.


What?

The piston, BCG are not in line with the bore on the AK, they sit above it and add to the muzzle rise during fire. It is completely different than what is talked about in this thread


well, it still has a roughly similar bore offset to the AR-15 and does benefit from the same principle of linear recoil transfer due to the low bore axis. the main reason that AKs recoil more than ARs is they are typically way over gassed.

Hamel  [Team Member]
2/22/2011 9:09:25 PM

Originally Posted By Badger66:
Originally Posted By kap_x:

Originally Posted By Mal_means_bad:
Also note the location of the charging handle on the first AR15's:
http://t1.gstatic.com/images?q=tbn:ANd9GcQBvAlo-lyxY8Q_dM_l_GCC7xhpxfBOP3HJ9wQstBs3o5b3LKhXLA&t=1

The "carry handle" was never meant for carrying, it's a protective structure around a charging handle that is no longer there, similar to the FAMAS.

I'm sure you could work out the recoil mechanism to drop the cheek weld some, but the first AR's also had a CH in the way, between the two it was best to leave well enough alone.

Excellent point!


Looks like you can reach the bolt catch when you pull back the charging handle without having to take your hand off the pistol grip! Stoner had it worked out after all.
If memory serves me correctly they had to move the charging handle cause it got too hot to touch after sustained firing.

Capt-Planet  [Team Member]
2/22/2011 9:11:52 PM
Originally Posted By Badger66:
Originally Posted By kap_x:

Originally Posted By Mal_means_bad:
Also note the location of the charging handle on the first AR15's:
http://t1.gstatic.com/images?q=tbn:ANd9GcQBvAlo-lyxY8Q_dM_l_GCC7xhpxfBOP3HJ9wQstBs3o5b3LKhXLA&t=1

The "carry handle" was never meant for carrying, it's a protective structure around a charging handle that is no longer there, similar to the FAMAS.

I'm sure you could work out the recoil mechanism to drop the cheek weld some, but the first AR's also had a CH in the way, between the two it was best to leave well enough alone.

Excellent point!


Looks like you can reach the bolt catch when you pull back the charging handle without having to take your hand off the pistol grip! Stoner had it worked out after all.


That's actually a good point. Was the original charging handle reciprocating too? That would eliminate the need for a forward assist too...
Mach  [Team Member]
2/22/2011 9:13:25 PM
Originally Posted By SpacemanSpiff:
Originally Posted By Mach:
Originally Posted By novaDAK:
http://www.proxibid.com/AuctionImages/4103/31795/Detail/405.jpg

not unique to the AR15.


What?

The piston, BCG are not in line with the bore on the AK, they sit above it and add to the muzzle rise during fire. It is completely different than what is talked about in this thread


well, it still has a roughly similar bore offset to the AR-15 and does benefit from the same principle of linear recoil transfer due to the low bore axis. the main reason that AKs recoil more than ARs is they are typically way over gassed.



while both bolts are obviously in line with the bore, there is much more mass above the bore on the bolt carier in the AK than there is on the AR. Pluse there is a huge honkin piston moving above the bore in the AK and there is none in the AR. That makes a big difference, plus the mass difference of the bullet.

What do you mean by over gassed?
David4327  [Team Member]
2/22/2011 9:13:27 PM
Originally Posted By SpacemanSpiff:
Originally Posted By Rem700PSS:
Just poor design





I don't think I have ever seen you post anything that would cause me to believe you are over the age of twelve.


LOL he is pretty funny if he is 12.
Mach  [Team Member]
2/22/2011 9:14:40 PM
Originally Posted By Capt-Planet:
Originally Posted By Badger66:
Originally Posted By kap_x:

Originally Posted By Mal_means_bad:
Also note the location of the charging handle on the first AR15's:
http://t1.gstatic.com/images?q=tbn:ANd9GcQBvAlo-lyxY8Q_dM_l_GCC7xhpxfBOP3HJ9wQstBs3o5b3LKhXLA&t=1

The "carry handle" was never meant for carrying, it's a protective structure around a charging handle that is no longer there, similar to the FAMAS.

I'm sure you could work out the recoil mechanism to drop the cheek weld some, but the first AR's also had a CH in the way, between the two it was best to leave well enough alone.

Excellent point!


Looks like you can reach the bolt catch when you pull back the charging handle without having to take your hand off the pistol grip! Stoner had it worked out after all.


That's actually a good point. Was the original charging handle reciprocating too? That would eliminate the need for a forward assist too...


I didn't know that. Interesting.
2manytoys  [Member]
2/22/2011 9:15:31 PM
Originally Posted By Frank_Castle:
Originally Posted By widerstehe:
It's a couple inches or so, right? I mean, forget about the carry handle for a moment. Even flat top uppers come with the front sight post so high up. Wouldn't the gun benefit from having low profile sights? I was thinking about this after seeing the Benelli MR1, which I don't like, but I do like the sights better than the AR.


It was explained to me (during BRM) that the barrel is actually slightly tilted upward and thus the bullet arcs. The point of aim matches at 25 meters and 300 meters.
I have the latest FM on the M16/M4 and it mentions that somewhere in the technical section also.


The barrel is only tilted up in relation to the line of sight, the same as with every other rifle,sporting or military.
Combat_Jack  [Team Member]
2/22/2011 9:16:10 PM
The AK uses a lot of gas. Some is vented out after the piston begins to move to the rear. In order to lower rate of fire, the trigger is controlled rather than the bolt, as in the AR.

Basically, the bolt on an AK is fast, and ROF is slowed by a cable rather than weight as in an AR.

It helps with reliability, but has some costs.
Mach  [Team Member]
2/22/2011 9:16:14 PM
Originally Posted By David4327:
Originally Posted By SpacemanSpiff:
Originally Posted By Rem700PSS:
Just poor design





I don't think I have ever seen you post anything that would cause me to believe you are over the age of twelve.


LOL he is pretty funny if he is 12.


wow so he joined when he was 4. That is awesome.
jblomenberg16  [Member]
2/22/2011 9:16:44 PM
Originally Posted By Frank_Castle:
Originally Posted By widerstehe:
It's a couple inches or so, right? I mean, forget about the carry handle for a moment. Even flat top uppers come with the front sight post so high up. Wouldn't the gun benefit from having low profile sights? I was thinking about this after seeing the Benelli MR1, which I don't like, but I do like the sights better than the AR.


It was explained to me (during BRM) that the barrel is actually slightly tilted upward and thus the bullet arcs. The point of aim matches at 25 meters and 300 meters.
I have the latest FM on the M16/M4 and it mentions that somewhere in the technical section also.


The barrel is in a straight line, but when you line up the front and rear sights they do not form a line parallel to the bore. They actually form a line that slopes slightly from rear to front. That will intersect the trajectory of the bullet at 25m if that is your "zero" distance, 50m if that is your zero etc.

The same phenomenon is true on just about any gun with the sights above the bore, irons or optics. The bullet rises up to meat the sight line because you end up pointing the barrel at a slight up-angle relative to the sight line.

Mach  [Team Member]
2/22/2011 9:17:09 PM
Originally Posted By Combat_Jack:
The AK uses a lot of gas. Some is vented out after the piston begins to move to the rear. In order to lower rate of fire, the trigger is controlled rather than the bolt, as in the AR.

Basically, the bolt on an AK is fast, and ROF is slowed by a cable rather than weight as in an AR.

It helps with reliability, but has some costs.


Didn't know that thanks
A_Free_Man  [Team Member]
2/22/2011 9:19:59 PM
Originally Posted By ColonelHurtz:
The sights aren't high, the bore is low.
Straight line design.


Yes, and who decided that sights have to be low to the bore? What makes that better?

Fact is, it doesn't.
Banditman  [Team Member]
2/22/2011 9:20:27 PM

Originally Posted By operatorerror:

Originally Posted By Combat_Jack:
So, how do you propose you would get your head low enough to see the sights?

A bolt and buffer system like the FAL would work. But I'm sure there's a reason why it wasn't used.

That is why I sold my nice FAL. It literally bruised my cheek when I shot it

Rem700PSS  [Team Member]
2/22/2011 9:32:44 PM

Originally Posted By Mach:
Originally Posted By David4327:
Originally Posted By SpacemanSpiff:
Originally Posted By Rem700PSS:
Just poor design





I don't think I have ever seen you post anything that would cause me to believe you are over the age of twelve.


LOL he is pretty funny if he is 12.


wow so he joined when he was 4. That is awesome.
And I was only smarter than about half of the people here at that time.

Bob1984  [Team Member]
2/22/2011 9:34:04 PM
The originators of the concept:





A Swiss rifle using this layout:



One of our early uses of this layout:



Another American weapon using a straight line layout:



The purpose of a straight-line layout is to offer better recoil control by transferring the recoil energy directly into the firer's shoulder, reducing muzzle climb in the process. This is particularly important in automatic weapons. Many grenade launchers also use a straight-line layout for the same reason:







LARRYG  [Team Member]
2/22/2011 9:44:26 PM
Originally Posted By Bob1984:
Another American weapon using a straight line layout:






Sorry, the M14 was not a straight line layout.

That's why the AR10 was more controllable on full auto.

Keith_J  [Team Member]
2/22/2011 10:14:59 PM

Originally Posted By LARRYG:
Originally Posted By Bob1984:
Another American weapon using a straight line layout:

http://www.fas.org/man/dod-101/sys/land/M14A1.JPG




Sorry, the M14 was not a straight line layout.

That's why the AR10 was more controllable on full auto.


They TRIED to make it so with the funky stock. It still didn't work. Same problem with the BAR which despite the hype, was far less effective a SAW than the M60.

Yes, the AR10 was far better in full auto but with 20 round magazines, it still pales to the M60 with hundred round belt.

LARRYG  [Team Member]
2/22/2011 10:21:44 PM
Originally Posted By Rem700PSS:

Originally Posted By Mach:
Originally Posted By David4327:
Originally Posted By SpacemanSpiff:
Originally Posted By Rem700PSS:
Just poor design





I don't think I have ever seen you post anything that would cause me to believe you are over the age of twelve.


LOL he is pretty funny if he is 12.


wow so he joined when he was 4. That is awesome.
And I was only smarter than about half of the people here at that time.



And it's been a downhill slide for you ever since.
0699TeufelHnd  [Team Member]
2/22/2011 10:29:11 PM
Originally Posted By Combat_Jack:
So, how do you propose you would get your head low enough to see the sights?

Especially with a fucking brain bucket on.
LARRYG  [Team Member]
2/22/2011 10:38:44 PM
Originally Posted By 0699TeufelHnd:
Originally Posted By Combat_Jack:
So, how do you propose you would get your head low enough to see the sights?

Especially with a fucking brain bucket on.


That always brings to mind a video of when we first went into Iraq. A camera crew was with what appeared to be a squad or Marines and in the background, you hear "put your fucking brain bucket back on".

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