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Posted: 10/25/2012 6:43:25 AM EDT
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I am seeking a healthy discussion on the issue of AR-15 forearms, specifically the significance of standard/drop-in handguards versus free floating handguards. At the moment, my rifle is free floated, and I very much appreciate the feel of my DD Omega Rail. But I could not help but take notice recently of how I could cause the barrel to hardly move despite exerting a decent amount of pressure on it. Obviously being that my barrel is free floated, I can see whether my barrel is actually moving or not when I push my hand against it. This I happened to find intriguing. Being that my Grip-pod is seated all the way back on the rail, there will be very little pressure exerted on the barrel had I merely retained a standard handguard.
So why do I even mention this? Well, for someone such as myself that only shoots with irons, I honestly do not see why I would or ever should be concerned about barrel deflection. On the other hand, those who would use scopes, and especially bipods attached to the end of their rails, I can easily see how deflecting the barrel would alter POI, whereas those of us who utilize only irons, any barrel deflection can be tracked through both the front and rear sight. Scopes obviously do not provide that luxury. But I am merely speculating that iron sights are unaffected. Now, I have read that barrel harmonics are a factor as well in regards to free floating, but I honestly cannot speak on the matter as I do not know the consequences of harmonics on the issue of handguards. At any rate, I would like to see some intelligent discussions on this matter, especially in regards to what I presume is a trivial matter for iron shooters such as myself. |
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In a use such as yours it would probably just be barrel harmonics, which may or may not be a big deal, something that effects it will sometimes have a huge effect on one rifle and virtually none on another. If one is going for absolute accuracy free floating is reccommended primarily because it removes variables. My view for ARs if you're going to have rails anyway why not, there's little price or strength difference and maybe it shoots a little better, maybe not, but rare is the firearm made worse by freefloating.
In ARs the most visible effect of not free floating I've seen is heavily bagged or on a bipod with extended shot strings you will usually see vertical stringing in groups, sometimes severe. Remember as the temperature of metals change they behave differently, so that barrel you can barely flex may flex a little more. Also consider how minor the movements of sights are and how much of an effect they have on POI, lets say you witnessed 1/32" of movement that will have a very pronounced impact at distance. |
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Quoted:
I am seeking a healthy discussion on the issue of AR-15 forearms, specifically the significance of standard/drop-in handguards versus free floating handguards. At the moment, my rifle is free floated, and I very much appreciate the feel of my DD Omega Rail. But I could not help but take notice recently of how I could cause the barrel to hardly move despite exerting a decent amount of pressure on it. Obviously being that my barrel is free floated, I can see whether my barrel is actually moving or not when I push my hand against it. This I happened to find intriguing. Being that my Grip-pod is seated all the way back on the rail, there will be very little pressure exerted on the barrel had I merely retained a standard handguard. So why do I even mention this? Well, for someone such as myself that only shoots with irons, I honestly do not see why I would or ever should be concerned about barrel deflection. On the other hand, those who would use scopes, and especially bipods attached to the end of their rails, I can easily see how deflecting the barrel would alter POI, whereas those of us who utilize only irons, any barrel deflection can be tracked through both the front and rear sight. Scopes obviously do not provide that luxury. But I am merely speculating that iron sights are unaffected. Now, I have read that barrel harmonics are a factor as well in regards to free floating, but I honestly cannot speak on the matter as I do not know the consequences of harmonics on the issue of handguards. At any rate, I would like to see some intelligent discussions on this matter, especially in regards to what I presume is a trivial matter for iron shooters such as myself. You can't see the barrel move unless there is is something wrong mechanically. As the bullet slams into the rifling, the barrel moves in an opposite direction. You can't see it, but if this motion is interrupted by sling pressure, bi pod pressure or just a non-floated handguard POI can be affected. |
| National match service rifles are all free floated with a forearm that maintains the stock appearance. This certainly helps world class shooters, such as the AMU, shoot tiny groups at 600 meters with iron sights. It is unlikely that you would ever notice the difference. |
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Your barrel doesn't have to move very much at the tip to move the POI at 100 yards.
A displacement of only .010" at the muzzle of a 16" barrel equals 2.25" at 100 yards IF the barrel flexed at the attachment to the receiver, which it does not... it bows, so the actual angle at the end of the barrel is much greater. My math was best case scenario, and the movement of the POI would be much greater than 2-1/4". For a man sized target at 100 yards this may be acceptable, but what about at 300 yards? Joe |
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Quoted:
Your barrel doesn't have to move very much at the tip to move the POI at 100 yards. A displacement of only .010" at the muzzle of a 16" barrel equals 2.25" at 100 yards IF the barrel flexed at the attachment to the receiver, which it does not... it bows, so the actual angle at the end of the barrel is much greater. My math was best case scenario, and the movement of the POI would be much greater than 2-1/4". For a man sized target at 100 yards this may be acceptable, but what about at 300 yards? Joe See now that is some very good information. Merely resting the rifle on the barrel resulted in a movement of 1mm, so yeah, by your rough estimates that can result a noticeable change in the POI. |
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