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Posted: 12/24/2003 12:12:39 PM EDT
Nuts, I was following a thread where there was
some disagreement over whether or not mounting an ACOG onto a SIR raised the scope too high or not. I was wanting to find out if that question was ever resolved. So of course, naturally I've lost the thread. Anybody know?

Thanks
Link Posted: 12/24/2003 12:45:09 PM EDT
It is of course lower than the carry handle mount which is good. However its far from ideal. Anything higher or lower than the iron sight height is not ideal. The only way to get the same height as the irons is to do a direct flat top mount. The issue is not trajectory so much as it is consistent cheek weld to the stock. With the SIR you cannot accomplish this with your cheek bone. You can get a jaw weld and hold your head still so you don't induce parallax error but it is more difficult than simply laying your head on the stock. So in essence its more of an ergonomics issue than one of practical utility.
Link Posted: 12/24/2003 2:53:16 PM EDT
I think it is as good as it gets being up a little higher than the irons for good reason. A unity power scope(no magnification like a red dot/ reflex) that are designed to replace irons, need to be where the irons are so you have the irons able to work thru the optic if it fails. That's what the military decided to do after much time in field trials. The magnified optics such as a ACOG are just that, magnified and not used like an iron or unity optic. With an iron you have to peep thru a very small hole and line it up perfectly with a small front sight post way out front, that is where a cheek weld is so much more critical than using the very large occular rear end of a magnified optic. If you look at any of the military sniper scopes in use, domestic or foreign, any military you can find, in any generation, they are generally always placed higher than the iron's for good reason. When a sniper/counter sniper is scanning for targets of oportunity, it is much easier and quicker to engage a target, especialy if it is moving, if you have the ability to move faster yourself, and that isn't done as well if you are snuggled too low behind the glass. A magnified glass has a much larger occular to look into that is much more forgiving than an iron, but you also have a field of view that is limited to more like a tunnel. Since your in more of a tunnel you need to be able to sweep a lot more in search of targets and engagement, especially multiple moving targets. Another thing to be considered by military snipers is retaining the ability to keep his vision of dangerous targets to the left or right from being totaly obscured by his own optic because it is too low and his ever so important peripheral vision is obstructed cause tyhe scope is too low. Designated targets are dif. than targets of opportunity. Designated targets are just simply put, something planned, but that is also much like a target bulls eye on a range, target shootin and doesn't have that much in common with targets of opportunity. Targets of opportunity mean not knowing what the distance will ever be, never knowing from where it will appear and or how many. An ACOG is a target of opportunity magnified scope, and not realy used for long range sniping and not generally used for designated targets. The ACOG was designed and issued to be in the carry handle and the irons are used under the optic thru the tunnel provided. With the advent of the flat top, the ACOG was lowered by some, but not that much generally speaking, since it still is not best used too low like at the ht. of irons for the reasons listed above. Trijicon have the irons on top of the ACOG for the purpose of quick reaction to an enemy being too close and not much time to react. It is also faster to engage a dangerously close target via irons over the optic, than by peeking thru the carry handle tunnel, but it does not mean to put the scope too low for the other reasons listed above. It is more generally accepted by military users of magnified 4 power scopes whether sniper or not, to keep that type optic up higher than the irons. If you look at the pic's shown on here and various other sources, such as the IDF, they have their ACOGS mounted way higher than the carry handle in the #19 throw lever mounts attached to a dovetail rail. The British with their 4 power optic's also higher, the Germans, Canada with their Elcan built up with exposed controls to a higher ht. than where the iron center line is. The militaries of the world have many reasons, some I have just listed. Cheek welds for irons are not necessarily the same for optics with magnification as a general rule in combat aplications, for good reason. For whatever it's worth that's my 2.5 cents worth. Good shootin, and have a Merry Christmas to all, Jack
Link Posted: 12/25/2003 2:05:25 AM EDT
[Last Edit: 12/25/2003 2:53:24 AM EDT by DevL]
Well what 3rdtk said has all kinds of holes in it. Edited to add: You know what. Im not gonna get in an argument on Christmas so I will delete my 4 paragraph rebuttal. Merry Christmas and good shooting. [:)]
Link Posted: 12/25/2003 5:25:41 AM EDT
Everything everyone says has holes in it and thats only because you can point out advantages and disadvantages in everything and what everyone says. I find myself taking advantage of the combined benefits the SIR and ACOG offer far more often and more regularly than I would take advantage of a slightly more solid cheek weld. I have ACOGs mounted to SIRs, to the flat top and to the carry handle. I shoot them all. The slightly improved cheek weld of getting the ACOG less than a 1/2" lower doesnt seem to do a thing for me, so I'll take it on the SIR. Someone else who much preffers the standard cheek weld will argue how its un-natural or how much they notice the difference when shooting etc. And I wont argue with them about it. In essence, the scope is not mounted too high to work. It may or may not be too high for you to work it, but it will work. If it works for you or not is another question. All I can say for sure is that it works for me, but does not for DevL.
Link Posted: 12/25/2003 9:45:08 PM EDT
I have been running a TA-11 on the carry handle for over 5 years. This year I went to a SIR 50 for various reasons. It took me a while to get used to having the ACOG that low. I know it would effect me even more putting it directly onto a flat top. But that is just me. To each his own.
Link Posted: 12/25/2003 9:51:28 PM EDT
Originally Posted By new-arguy: All I can say for sure is that it works for me
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And that folks is what counts at the end of the day...
Link Posted: 12/26/2003 2:04:49 PM EDT
[Last Edit: 12/26/2003 2:08:20 PM EDT by DevL]
Originally Posted By 3rdtk: I think it is as good as it gets being up a little higher than the irons for good reason. A unity power scope(no magnification like a red dot/ reflex) that are designed to replace irons, need to be where the irons are so you have the irons able to work thru the optic if it fails. That's what the military decided to do after much time in field trials. The magnified optics such as a ACOG are just that, magnified and not used like an iron or unity optic. With an iron you have to peep thru a very small hole and line it up perfectly with a small front sight post way out front, that is where a cheek weld is so much more critical than using the very large ocular rear end of a magnified optic. [red]This is incorrect. Looking through magnified optics with your head not in line with the optics induces parallax error. This shifts the POA relative to POI and causes accuracy degradation.[/red] If you look at any of the military sniper scopes in use, domestic or foreign, any military you can find, in any generation, they are generally always placed higher than the iron's for good reason. [red]Yes that good reason is that its a hack job. This is why you see guys in the field using duct taped cheek rests on M14s converted to M21s in the field. This is also why you see M24 and M40A1 sniper rifles with adjustable combs. Anything less is a hack job.[/red] When a sniper/counter sniper is scanning for targets of opportunity, it is much easier and quicker to engage a target, especially if it is moving, if you have the ability to move faster yourself, and that isn't done as well if you are snuggled too low behind the glass. [red]personal opinion. I move well head low or head high. Head down is how I box too so its natural.[/red] A magnified glass has a much larger ocular to look into that is much more forgiving than an iron, but you also have a field of view that is limited to more like a tunnel. [red]No its not MUCH more forgiving because of parallax error which I stated above. Thats why cheek weld is the mantra of precision shooting [/red] Since your in more of a tunnel you need to be able to sweep a lot more in search of targets and engagement, especially multiple moving targets. Another thing to be considered by military snipers is retaining the ability to keep his vision of dangerous targets to the left or right from being totaly obscured by his own optic because it is too low and his ever so important peripheral vision is obstructed cause tyhe scope is too low. [red]I really have no idea how a low optic harms periferal vision. That one blows my mind.[/red] Designated targets are dif. than targets of opportunity. Designated targets are just simply put, something planned, but that is also much like a target bulls eye on a range, target shootin and doesn't have that much in common with targets of opportunity. Targets of opportunity mean not knowing what the distance will ever be, never knowing from where it will appear and or how many. An ACOG is a target of opportunity magnified scope, and not realy used for long range sniping and not generally used for designated targets. [red]And yet it a designated marksman's rifle scope and is used at long ranges. Height of the scope has nothing to do with speed of its use... well unless you want to say lower is faster, I could agree with that.[/red] The ACOG was designed and issued to be in the carry handle and the irons are used under the optic thru the tunnel provided. [red]Because of the number of A2 receivers this was needed. Its still a hack job afterthought and not designed correctly[/red] With the advent of the flat top, the ACOG was lowered by some, but not that much generally speaking, since it still is not best used too low like at the ht. of irons for the reasons listed above. [red]Seems like the SOPMOD 2 upgrade wanted the optics that low where they SHOULD be instead of where ARMS wanted to put them.[/red] Trijicon have the irons on top of the ACOG for the purpose of quick reaction to an enemy being too close and not much time to react. [red]TA31 has the red dot in line with the scope for BAC use. It will be mounted at the proper height for all the Marine A4s now which is a step in the right direction.[/red] It is also faster to engage a dangerously close target via irons over the optic, than by peeking thru the carry handle tunnel, but it does not mean to put the scope too low for the other reasons listed above. It is more generally accepted by military users of magnified 4 power scopes whether sniper or not, to keep that type optic up higher than the irons. If you look at the pic's shown on here and various other sources, such as the IDF, they have their ACOGS mounted way higher than the carry handle in the #19 throw lever mounts attached to a dovetail rail. [red]Again a hack job. I suppose you think we should drop our rail systems and FF foreends so we can mount our IR lasers on the barrel like the IDF too? Oh wait thats not a pro ARMS thing to say so you cant say that.[/red] The British with their 4 power optic's also higher, the Germans, Canada with their Elcan built up with exposed controls to a higher ht. than where the iron center line is. [red]Actually the G36 uses optics low. The red dot sight mounted above the optic does not require a good cheekweld because the red dots are parallax free. Your previous statements are the red dots need to be lower and optics higher. Seems they did the opposite.[/red] The militaries of the world have many reasons, some I have just listed. Cheek welds for irons are not necessarily the same for optics with magnification as a general rule in combat aplications, for good reason. For whatever it's worth that's my 2.5 cents worth. Good shootin, and have a Merry Christmas to all, Jack [red]Obviosly our own military feels differently. There are no super high mounts that put the optics way up where the carry handle scopes used to be for the modern flattops. Not for the M4A1 and Not for the M16A4. Low rail height was speced for that reason for SOPMOD 2 upgrades and we all know it. On an optic like the TA31 you have a very small sweet spot to not have some of the optic occluded by the casing. With a proper iron sight cheek weld you bring the rifle up till your cheek touches the stock and your nose touches the charging handle. There, your in the perfect spot every time and there is no "learning" or "hunting" for the right spot. This makes the low scope faster not slower. This is simple physics and ergonomics. It can be worked around and the end result is VERY small but dont try to tell us the ARMS SIR flaw is a design feature.[/red]
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Link Posted: 12/26/2003 2:21:38 PM EDT
OK:) Lets correct the incorrect respones, one at a time. Naturaly the cheek weld for the magnified optic is going to be dif. than the iron's. However paralax is not going to be an issue, since a sniper trains to the equipment and know enough to move their cheek to the proper alignment. Jack
Link Posted: 12/26/2003 2:30:08 PM EDT
(2) General certified issue sniper weapons can't be compaired to a hastilly put together weapon that has a duck tape cheek rest and or non issue mounts placed on a less than a genuine stock and sniper weapon. Field expedient isn't what I refered to. Jack
Link Posted: 12/26/2003 2:36:44 PM EDT
Not opinion, just historical fact as shown by the way weapons have generaly been set up by the (vast majority) of miltary sniper weaponns shown in photos. Ya can't move you head or eye as well down too low, compared to a little higher. Jack
Link Posted: 12/26/2003 2:48:34 PM EDT
(4)It is much more forgiving, because you have a cheek weld that allows the eye ball to move in all the directions the glass allows, apposed to a tiny little rear iron peep hole. If you line up with a peep, and move your eye ball at all, you don't see the front sight bead completly disapears. There is just no comparison between the two, just putting the two beside each other and actually trying, shows their is no question of what is more forgiving. Jack
Link Posted: 12/26/2003 3:18:10 PM EDT
(5) Periferal vision isn't helped if the head is down so low to because an optic is mounted too low. Depending if the weapon is used as a left or right handed shooter, the periferal vision to the left or right can be blocked more easily by the blind spot to one side or the other by the scopes own housing and sometimes it's mount, and head ht being too low to allow good periferal vision. The terrain for a sniper is not normaly what is found at the local range. For instance, if a right handed sniper on top of a crest is down too low on a weapon, a blind spot can be created to his lower right, the periferal may not see an approaching enemy crawling up the hill to his lower front right. The angle from where the other guy cometh, can be out of the line of sight, and that will happened less with higher mounted optic's than real low mounting. You also have to consider defense, not just offense. Jack
Link Posted: 12/26/2003 3:23:40 PM EDT
Originally Posted By MagnumLover: Nuts, I was following a thread where there was some disagreement over whether or not mounting an ACOG onto a SIR raised the scope too high or not. I was wanting to find out if that question was ever resolved. So of course, naturally I've lost the thread. Anybody know? Thanks
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You ALL are making this way too complicated. Is the 1/2" too much for your cheekweld? If it is don't mount it on a SIR. You're welcome, H
Link Posted: 12/26/2003 3:30:02 PM EDT
(6) Designated marksman can mean several things and has nothing per-se to do with the optics, and especialy nothing to do with a designated target. Designated target means the sniper is after somone/something very special. The equipment will also be very special to the mission! Targets of oportunity mean just that, as I have fully explained, and why they are best set a little higher, with less magnification as you don't have to make a positive ID, that I have also very fully explained. Jack
Link Posted: 12/26/2003 3:48:04 PM EDT
I think I will take the advise of a couple and not try to give any more solid facts to those who don't want to know and just close with the following. Mounting in the carry handle was certainly no hack job, and they have been employed thu out the world to this day because they work very well. Obviously the history books of sniper work thru out many wars do not sit on the shelfs of some, Suggest thy GETTING SOME. (Super high mounts)? certainly isn't what the discussion was, we were talking less than a 1/2" higher than the flat top, and about 1" lower than the carry handle, and factual history that can be verified, and mounts on a M14 have nothing to do with mounting optics on a strait line stock found on the M16. GEEE's Jack
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