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Thread: Argument for pencil barrels?

  1. #21
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    Quote Originally Posted by friendlyfireisnt View Post
    I did a test a few months back, two different lightweight barrels, three ammo types, three 10-shot groups from each ammo.

    One of those barrels averaged with one load, right around 1.25moa groups. That was a Daniel Defense CHF barrel.

    My Larue Stealth was averaging about .95moa for 5-shots.

    Right after I did the test, I pulled the 3-9x leupold scope off the stealth, put it on the DD. I won't notice the 1/4" loss of accuracy but I will notice the lost weight.
    That's fantastic! You can't ask for much more than that from a chrome lined barrel with random factory ammo. You could easily do sub MOA if you dialed in a handload. The stealth is a stainless barrel, made from Lothar Walther blanks I think, so it's a bona fide precision piece. I would expect it to do better, much better with handloads, than a CHF barrel from anyone.

  2. #22
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    Quote Originally Posted by HansTheHobbit View Post
    I've seen that video before, and what they're not taking into account is that the rifling was cooked long before the barrels failed. That's the problem with meltdown videos is that they only prove how the rifle would perform under totally unrealistic conditions. Not only can no one carry that much ammo, but no one can fire that fast with any degree of accuracy. I would also have liked to see a temperature comparison at different stages. The heaver barrel didn't droop because of its rigidity, and that may have added a few hundred rounds. I can almost guarantee that the M4A1 got hotter because it cooked off rounds, whereas the M4 didn't. I think there's a really good chance that the throats of both barrels reached critical temp at about the same round count. However, I do think the video clearly demonstrates the folly of the M4 profile. Simply adding a few grams of material behind the gas journal would have kept it going longer, and removing the entire profile around the M4 cut would not have hurt anything. Not only would the barrel be lighter, but it would feel much lighter because of the redistribution of material.

    Now normal sustained firing, in short bursts, may prove to be another story. That's what the R&D guy I spoke with didn't really know. He knew for a fact that full auto dumps would destroy the throat of any barrel, even a full bull profile, in the same amount of time, but he didn't know how many rounds a heavier barrel could buy you during normal rates of fire. I would love to see a manufacturer take two barrels, one light and one heavy, put both through the same course to simulate a realistic gunfight, and see how fast the throats get to critical temp.
    I agree completely an tried to address this in post #14.

    I do not own any 'pencil' profiled barrels so I unfortunately cannot give an example of what kind of accuracy and precision they might be able to give for any given firing schedule.

  3. #23
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    The barrel is the radiator. The greater the mass, particularly around the chamber area, the greater amount of heat the rifle can handle. Even a semi auto rifle can get a barrel pretty hot. I had a carbine with a government profile stainless steel barrel that I got so hot, the barrel turned a bronze color. I wasn't doing mag dumps, but I did purposely put a lot of round through it to see how it would hold up. It held up pretty well. Barrel is still shoots good and is being passed on to a younger member of the family.

    Point is, if you want as lightweight barrel, get one. Rifling will wear faster because the barrel will get hotter, but so what? Or, you can get a barrel with heavier profile. The SOCOM barrel is trending right now and has proven to be more durable than the M4 barrel. It's heavier, but again, so what? TANSTAAFL
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  4. #24
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    Quote Originally Posted by MistWolf View Post
    The barrel is the radiator. The greater the mass, particularly around the chamber area, the greater amount of heat the rifle can handle. Even a semi auto rifle can get a barrel pretty hot. I had a carbine with a government profile stainless steel barrel that I got so hot, the barrel turned a bronze color. I wasn't doing mag dumps, but I did purposely put a lot of round through it to see how it would hold up. It held up pretty well. Barrel is still shoots good and is being passed on to a younger member of the family.

    Point is, if you want as lightweight barrel, get one. Rifling will wear faster because the barrel will get hotter, but so what? Or, you can get a barrel with heavier profile. The SOCOM barrel is trending right now and has proven to be more durable than the M4 barrel. It's heavier, but again, so what? TANSTAAFL
    Again, I'm not convinced that heavier profiles preserve the rifling. The R&D guy I was talking to had some equation that explained how different materials could sink heat at different rates, and the numbers for barrels steels showed that you would have to fire pretty slow so as not to exceed the ability of the meat of the barrel to draw heat away from the rifling. My hypothesis is that a barrel can dissipate heat at the same rate at which it is sinked from the rifling. In other words, if you're firing slowly enough not to overheat the rifling, then the barrel is going to dissipate that heat just as quickly.

    That's why I'm so focused on the rifling, as opposed to where the barrel fails or anything else. I've never seen any hard evidence that thicker barrels actually preserve rifling in any meaningful way. Thus, their only benefit would be a slightly higher round count before expansion-induced loss of accuracy. But, if you're firing that quickly, then the rifle has almost certainly gone from SPR duty to battle rifle, so the only disadvantage in that case is that you would have to wait a few minutes before the rifle was back to its original POI. I could be totally wrong, but as far as I know, no one has ever tested this specifically.

  5. #25
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    Quote Originally Posted by MistWolf View Post
    The barrel is the radiator. The greater the mass, particularly around the chamber area, the greater amount of heat the rifle can handle. Even a semi auto rifle can get a barrel pretty hot. I had a carbine with a government profile stainless steel barrel that I got so hot, the barrel turned a bronze color. I wasn't doing mag dumps, but I did purposely put a lot of round through it to see how it would hold up. It held up pretty well. Barrel is still shoots good and is being passed on to a younger member of the family.

    Point is, if you want as lightweight barrel, get one. Rifling will wear faster because the barrel will get hotter, but so what? Or, you can get a barrel with heavier profile. The SOCOM barrel is trending right now and has proven to be more durable than the M4 barrel. It's heavier, but again, so what? TANSTAAFL
    I wish the 6920 had an M4A1/SOCOM barrel option. I prefer strength and durability at the expense of a little bit of weight.

    I would like to see a comparison of a pencil barrel w/suppressor and a good string of fire vs a heavier profile w/suppressor in the same conditions and compare the accuracy.
    Last edited by Falar; 07-18-16 at 11:34.

  6. #26
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    I prefer pencil barrels.
    Since I no longer feel the need for mag dumps, but do like a lighter gun.

  7. #27
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    Quote Originally Posted by ColtSeavers View Post
    Don't know if this reply is specifically directed at me or not, but in case it is, I was simply showing one of the instances that a heavier profile barrel shines as this specific example was brought up by previous members' posts. I really should have used the quote feature to further illustrate that intent. My apologies for not doing so.

    As I've posted in other similar threads, if you're going to ruck it all day go lighter. If you're going to go from the safe to the car to the bench, go with whatever profile you want. If you're going to mag dump or shoot for extreme accuracy and precision, go heavier. Generally speaking of course.
    I don't disagree. What I do disagree with is the relevance of the test itself. As another poster mentioned the rate of fire and the volume is completely unrealistic even in a military application. My opinion regarding any firearm is to have a specific role(s) for each and nothing else. Nowhere in my thinking is there a role for a rifle to be capable of unrealistic volumes of full auto fire. Making the benefit of the heavier barrel a non starter.

    MM

  8. #28
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    Quote Originally Posted by Mysteryman View Post
    I don't disagree. What I do disagree with is the relevance of the test itself. As another poster mentioned the rate of fire and the volume is completely unrealistic even in a military application. My opinion regarding any firearm is to have a specific role(s) for each and nothing else. Nowhere in my thinking is there a role for a rifle to be capable of unrealistic volumes of full auto fire. Making the benefit of the heavier barrel a non starter.

    MM
    I'm not going to disagree with your opinion or intended purposes. However, I must disagree with is the rate of fire and volume being unrealistic and there being no real military application for a heavier profiled barrel that can withstand higher consecutive round counts if not cyclic rate as well. There have been numerous times FOBs (for instance) have come under attack and the entire FOB has come within a magazine or two, per person, of going black. Pick a war (Afghanistan and Iraq being the two most relevant) and you can find the instances.

    Now, with that being said, I will admit that a lot of that expended ammo, barrel melting round count was not actually on target, and that getting more rounds actually on target should always be both the priority and goal, but it still created an area of denial of that kept the enemy from advancing or overtaking them easily.

    But, this is starting a drift, and I will pursue this tangent no more.

  9. #29
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    Quote Originally Posted by ColtSeavers View Post
    I'm not going to disagree with your opinion or intended purposes. However, I must disagree with is the rate of fire and volume being unrealistic and there being no real military application for a heavier profiled barrel that can withstand higher consecutive round counts if not cyclic rate as well. There have been numerous times FOBs (for instance) have come under attack and the entire FOB has come within a magazine or two, per person, of going black. Pick a war (Afghanistan and Iraq being the two most relevant) and you can find the instances.

    Now, with that being said, I will admit that a lot of that expended ammo, barrel melting round count was not actually on target, and that getting more rounds actually on target should always be both the priority and goal, but it still created an area of denial of that kept the enemy from advancing or overtaking them easily.

    But, this is starting a drift, and I will pursue this tangent no more.
    I've never heard of any action where anyone came remotely close to melting a barrel. Damaging the throat maybe, but not melting a barrel. Of course with the exception of belt fed machine guns, but that's another story. It's not hard to melt a barrel when you've got an entire palette of belts at your disposal.

  10. #30
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    Quote Originally Posted by HansTheHobbit View Post
    I've never heard of any action where anyone came remotely close to melting a barrel. Damaging the throat maybe, but not melting a barrel. Of course with the exception of belt fed machine guns, but that's another story. It's not hard to melt a barrel when you've got an entire palette of belts at your disposal.
    ETA: the one instance of a barrel melting that I know of for sure was a fifty cal in WWII during the Battle of the Bulge. The Germans were all hopped up on Pervatin, and they were rushing this cut off foxhole like mad men. These guys were cut off and being rushed by waves of tweakers with a death wish so fast that they didn't have time to change the barrel. It did finally blow out. I'm sure there are other instances, but that's what it takes. Keep in mind that this was essentially the worst place to be during the worst battle of WWII.

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