WTB 16" AR barrel or complete upper FTF Houston

[cajunautoxer]

Since I wasn't able to find an 20" WOA upper local. I've decided to build a KISS rifle, something easy to carry during carbine classes (if I ever get to go again). So now I'm searching for a 16" 5.56 light weight pencil barrel or a complete upper with pencil barrel. Let me know if you have one. It can be new or used.

[The Annoyed Man]

Since I wasn't able to find an 20" WOA upper local. I've decided to build a KISS rifle, something easy to carry during carbine classes (if I ever get to go again). So now I'm searching for a 16" 5.56 light weight pencil barrel or a complete upper with pencil barrel. Let me know if you have one. It can be new or used.

Why not use a M4 profile barrel instead of the pencil barrel? You can build a pretty light weight carbine without having to resort to the reduced accuracy of pencil barrels.

[cajunautoxer]

Since I wasn't able to find an 20" WOA upper local. I've decided to build a KISS rifle, something easy to carry during carbine classes (if I ever get to go again). So now I'm searching for a 16" 5.56 light weight pencil barrel or a complete upper with pencil barrel. Let me know if you have one. It can be new or used.

Why not use a M4 profile barrel instead of the pencil barrel? You can build a pretty light weight carbine without having to resort to the reduced accuracy of pencil barrels.

I have 4 lowers sitting at my house right now. As of today this is what I want to do with them.

KISS 5.56 No FA and shell deflector, CF hand guards ect
20" rifle bc sometimes I get the itch to start shoot HP
6.8 or 6.5 rifle
5.45

Now when say reduced accuracy what exactly do you mean? Barrel flex or when the barrel is too hot? I don't expect to loose that much in accuracy. I've got plenty of other rifles for that. The only down fall to a pencil barrel is when adding a supressor then I may have some issues. I have a buddy that has <10,000 rounds thru his and it still shoots pretty good.

[cajunautoxer]

TTT

[jayg0351]

PM sent

[cajunautoxer]

PM sent

I thought I responded. I'm looking for a WOA 20" barrel (for shooting HP) or a 16" pencil barrel for a KISS rifle. Thanks for the offer.

Still Looking

[The Annoyed Man]

Since I wasn't able to find an 20" WOA upper local. I've decided to build a KISS rifle, something easy to carry during carbine classes (if I ever get to go again). So now I'm searching for a 16" 5.56 light weight pencil barrel or a complete upper with pencil barrel. Let me know if you have one. It can be new or used.

Why not use a M4 profile barrel instead of the pencil barrel? You can build a pretty light weight carbine without having to resort to the reduced accuracy of pencil barrels.

I have 4 lowers sitting at my house right now. As of today this is what I want to do with them.

KISS 5.56 No FA and shell deflector, CF hand guards ect
20" rifle bc sometimes I get the itch to start shoot HP
6.8 or 6.5 rifle
5.45

Now when say reduced accuracy what exactly do you mean? Barrel flex or when the barrel is too hot? I don't expect to loose that much in accuracy. I've got plenty of other rifles for that. The only down fall to a pencil barrel is when adding a supressor then I may have some issues. I have a buddy that has <10,000 rounds thru his and it still shoots pretty good.

There are three things in your proposed build that are going to adversely affect your accuracy:

1. Barrel Weight: ALL barrels vibrate when a round is discharged. Two things cause this...the vibrations caused by the detonation itself, and vibration as the bullet gets driven down the bore. Given two barrels of equal length but unequal exterior diameters, the amplitude of the vibrations in the thinner barrel will be higher than the amplitude in the heavier barrel. For all practical purposes, the amplitude of the vibration is a measure of the amount of deflection off-center of the bore as the barrel vibrates. Thus, the amount of deflection off of center as the bullet exits the muzzle will be higher in a lighter weight barrel than in a heavier barrel. (Similarly, given two barrels of equal diameter but unequal length, the longer barrel will deflect more than the shorter barrel, because the shorter a barrel is in relation to its length, the stiffer it will be. So Strike One against your accuracy is a pencil thin barrel, which is lighter than even a standard weight barrel. A standard barrel which has the same diameter as an M4 barrel, but without the cuts for the grenade launcher, will be much more accurate than a pencil barrel, without adding that much weight to the rifle.
2. Heat: Heat changes both the hardness of the barrel metal, and the dimensions of the barrel. The magnitude of change is very small, but it is enough to throw off accuracy. Even free-floated heavy barreled rifles will lose accuracy to heat if it builds up enough, because the amplitude of barrel harmonics go up as the metal "softens." A barrel is a heat-sink, meaning it is a place where heat goes to hang around. A heavier barrel can absorb more heat than a lighter barrel can before the effects of heat start producing point-of-impact deflections.
3. Free-floating: When a barrel is free-floated, that means that the only place at which the barrel contacts the rest of the rifle is the point at which it threads into the action. In an AR platform rifle, you also have a gas block, which is effectively a weight which can either dampen or magnify the amplitude of barrel vibration, and which is loosely attached to the receiver via the gas tube. You can't get around the need for the gas block and tube in an AR rifle, but you can otherwise free-float the barrel by ditching the standard forend setup and buying a free-floated handguard from any number of manufacturers, in any number of styles and configurations. This has the advantage of permitting the barrel to attain its natural harmonic state under firing and heat, without having the rest of the rifle pressing against it in sideways deflection. That deflection will throw a shot off center, and it gets worse as the barrel heats up.

So, you can get better heat management with less shot deflection by ditching the pencil barrel for a standard weight barrel. You can get better vibration management with less shot deflection by ditching the pencil barrel for a standard weight barrel. And finally, you can get less shot deflection due to heat and barrel harmonics by free-floating the barrel.

I know all of this stuff is rudimentary, but you have to ask yourself why you wouldn't want to take these steps, if the cost difference is negligable and the payoff is a more accurate rifle. Heck, even if you just go to the standard barrel weight and don't change anything else, your accuracy will likely be better.

And it isn't just cold-bore shooting we ought to be concerned about. Believe me....if you go to the range with two different ARs—one like what you're proposing, and one exactly like it but with a standard weight barrel—and you put 100 rounds through both of them, you're going to find even less barrel deflection in the heavier barrel after 100 rounds than you would see in the lighter barrel. Neither rifle is going to be a "sniper" weapon, but a carbine that will maintain accuracy out to 250-300 yards is a more useful rifle than one that is well outside of its element beyond 100 yards. You stated that you don't expect to lose that much accuracy.....I beg to differ. Now, if you're never going to shoot anything beyond 50 yards, and whatever you're shooting at is larger than a 4" circle, then your loss of accuracy will not be that noticeable. But that doesn't mean that it isn't there....you're just close enough that accuracy is less of an issue.

Your mileage may vary, and it really does depend on what your intended use is, but that's just my 2¢.