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Thread: Anyone read LAV's G&A Article on AR's?

  1. #21
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    Quote Originally Posted by Alpha Sierra
    Maybe it's my questioning nature, but this:

    Makes no sense.

    What disaster? What is the sequence of events that leads to it? And why is the DI gas system a critical element of that failure?

    And SS barrel life not enough? It depends on your standards and your application. A SS barrel will give minute of man accuracy at 300 meters for 8 -10K rounds. Sure, CL will last a lot more. But how much is enough? There is no cut and dried answer.
    I think we have to look at the two different worlds (LAV's and CIVY's). People like Larry and the group he left shoot more ammo than we can even imagine. They would have a SS barrel shot out in no time flat. Most Civy shooters only run 3-4K a YEAR through their weapons (if that). Most folks on the "bubble gum" forums most likely only shoot 500rds a year. So a SS barrel being used so little, is going to give the shooter a longer life than a HSLD guy.

    I think there is a need for a 16" SS platform that is capable of extreme accuracy in the .Mil world. There is also a need for it in the Civy world. I often times use my Recon AR to varmint hunt. Its accuracy lends itself well to this hobby and gives me some practice on moving targets.

    We (as Civy shooters) have to keep things in context and realize where the writer is coming from and understand to what audience he is giving advice to.




    C4

  2. #22
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    On a di gas system, the gas along with the carbon it contains is dumped into the chamber area. Chrome plated chambers tends to be somewhat self-cleaning of carbon fouling. The carbon tends to stick more to the brass and not the chromed chamber, while on a unplated chamber it stick equally to both.

    Stainless steel barrels simply do not have the corrosion resistance and barrel life of a chrome lined barrel. A stainless steel barrel is moderately corrosion resistant and has a hardness of around 30-40 on the rockwell C scale. The chrome plating is extremely corrosion resistant and and has a hardness over what the C scale goes to. Stainless steel ar barrels are used in the military, but only on special weapons that are for special purposes(sniping and target shooting) and get a limited amount of rounds fired through them compared to g.i. weapons. Pat Rogers stated that Force Recon can go through 5,000-8,000 rounds from their primary and secondary weapons in two weeks of training. If stainless steel barrels were used they would have to be replaced every couple of weeks. Chrome lined barrels can easily go twice that.

    The chrome lined barrel on my ar will shoot around 1-1.5 MOA at 100 yds with good ammo and my sgt's stainless bull barreled ar will shoot around 0.5 MOA at the same range with the same ammo. The difference, which will not make any difference in my general purpose carbines role, simply is way to much of a difference for my sgt's urban sniper's rifle's role. Mine might have to work for several dozen or even several hundred rounds at a range of contact to several dozen yards, his only has to work for a magazine or two(or less) at 25 to 100 yds. Mine might go through a case of ammo in a month or two, his goes through a couple of cases a year. And a military or SWAT carbine can go through several cases a week.

  3. #23
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    A couple of points.

    1) Thats a Force unit in run up - its not firing that EVERY week

    2) Some units have two or three lowers issued and 6+ uppers. Tier1 units that do 5k+ rounds a week will not be troubles by a gun shitting the bed in the training -- friends I know have identical guns for that sort of stuff. And in expending that sort of round count - especially when some use suppressors -- other things die out before the barrel.

    3) DI does not dump gas into the chamber directly -- it dumps it intially into the bolt - which exits the carrier in various manners -- and then after unlocking some gas is expelled into the receiver opening -- the only gas directly dumped into the chamber is from the expended casing -- which is the same in a gas piston gun.

    4) I have a 16" Douglas middy SS barrel I use - its over 14k w/o a noticeable problems - inc some heavy fire periods (10+ mags in a "short" period of time). USNSWC Crabe did a shitload of testing (auto and endurance) with the Douglas barrels for the Mk12 and then later with the Lilja's -- the majority of issues I have seen with stainless barrels is due to their chambering -- not due to the fact they are stainless. I dont think SS barrels are for everthing -- but I would not discount them -- and I doubt that was LAV's intent either.
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  4. #24
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    Quote Originally Posted by KiloSierra
    On a di gas system, the gas along with the carbon it contains is dumped into the chamber area. Chrome plated chambers tends to be somewhat self-cleaning of carbon fouling. The carbon tends to stick more to the brass and not the chromed chamber, while on a unplated chamber it stick equally to both.
    By the time the extraction starts, the DI gas system pretty well spent... the gas that is blown back through the chamber comes from the bore in front of it and it is a concern with a piston system the same as a DI system. Check out the slo-mo video that rsilvers posted and you can see the gas blowback from the chamber of a piston upper very clearly.

    Quote Originally Posted by KiloSierra
    Stainless steel barrels simply do not have the corrosion resistance and barrel life of a chrome lined barrel. A stainless steel barrel is moderately corrosion resistant and has a hardness of around 30-40 on the rockwell C scale. The chrome plating is extremely corrosion resistant and and has a hardness over what the C scale goes to. Stainless steel ar barrels are used in the military, but only on special weapons that are for special purposes(sniping and target shooting) and get a limited amount of rounds fired through them compared to g.i. weapons. Pat Rogers stated that Force Recon can go through 5,000-8,000 rounds from their primary and secondary weapons in two weeks of training. If stainless steel barrels were used they would have to be replaced every couple of weeks. Chrome lined barrels can easily go twice that.
    Hard chrome lining is designed as a protection from environmental threats... the forward throat area of a gun wears out do to the high heat and pressures of the gas, as well as the mechanical torque and hammering of the bullet -- there is really no concern with "wearing" a bore out. The thing to keep in mind about hard chrome is that it is no different from *regular* chrome, other than it is actually applied in a thick enough layer that a hardness test can be done on it... but still it is very thin. Again, while it certainly offers some degree of protection, primarily it is there to keep the bore from rusting.

    Rescent test of several military barrels show that throat errosion is not what a lot of forum experts will try to tell you it is... cut a few shot out barrels in two and see what is going on, it is interesting as hell. I first started looking at this while researching hot spots and cook offs... you will see the relation between the two and that most of the info you get about "heat sinks" and all of that is just so much crap.

    Stainless barrels have had a rather good show with the military really and the life of them is not at all as bad as some say -- what is noted is that a SS barrels fails suddenly, it shoots pretty good right up to the end of its useful life and then takes a dump and dies -- while a chromemo/HC barrel will taper off gradually till it just aint worth keeping, but the end of life is harder to notice. If you take a look at the throat/leade areas of different barrels, you will see a distinct wear "pattern" with chromemo and SS.

    BTW: I dont like hooded front sights, they cause the shooter to naturally align the circle-in-a-circle and not the front sight post (which would almost never be center in the front circle) -- I know "I seem to have no problem getting them to line up while posing the draw down on myself in the bathroom mirror, while wearing every piece of tacticool nylon known to man"... the answer might be. So have your buddy get a box of stray cats and try to get a good sight picture while he is throwing the cats at you... naked.

    ETA: I actually started this before Kevin posted, but my two fingers were going as fast as they could
    Please let me know if I have offended you...
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  5. #25
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    3) DI does not dump gas into the chamber directly -- it dumps it intially into the bolt - which exits the carrier in various manners -- and then after unlocking some gas is expelled into the receiver opening -- the only gas directly dumped into the chamber is from the expended casing -- which is the same in a gas piston gun.
    Thank you, it's time someone said this. Some residue will blow out the carrier by the bolt into the extension but the barrel and chamber by and large makes its own.


    Gas primarily vents out the two front relief holes. Some residue blows by the rings and goes out the cam slot and by the head of the bolt but this is a small fraction.

    Some also comes out the rear relief hole(the thing near the FPRP hole) and also goes out past the tail end of the bolt to be deposited around the head of the firing pin and asociated areas of the carrier.

  6. #26
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    Quote Originally Posted by C4IGrant
    I think we have to look at the two different worlds (LAV's and CIVY's)...

    We (as Civy shooters) have to keep things in context and realize where the writer is coming from and understand to what audience he is giving advice to.
    Just came in from shooting; ready to type.

    Who is that audience? In this case, buyers of a Guns & Ammo special edition entitled, Tactical Guns and Gear. His conclusion referred to Joe Citizen and the requirement that he ought be able to effectively operate an M16.

    Here is why I think you get his intended audience wrong: "And frankly, if you are only attaching a simple weapon light to your carbine, a piece of Picatinny rail bolted onto your handguard works well. Picatinny-rail-system handguards came from the need to bolt on an IR laser (such as the ITI US GI-issued PEQ-2 unit) and have it retain zero. If this is not a requirement of your AR-15-style carbine, I would think long and hard before getting your rail system. Ask yourself whether you are getting it because you really need it or because you think it looks cool."

    Few, if any, of we CIVY's have an AN/PEQ-2A (or equivalent.) So, to whom is he addressing this comment? The same audience as the audience of the whole article? I think so.

    Zak Smith had a good article on slings. Someone named Patrick Sweeney had a couple of articles. I didn't note any bio info on him at the end of the articles. Who is he?
    "The very purpose of a Bill of Rights was to withdraw certain subjects from the vicissitudes of political controversy, to place them beyond the reach of majorities and officials and to establish them as legal principles to be applied by the courts." Justice Robert Jackson, WV St. Board of Education v. Barnette, 319 U.S. 624 (1943)

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  7. #27
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    Quote Originally Posted by Submariner
    Just came in from shooting; ready to type.

    Who is that audience? In this case, buyers of a Guns & Ammo special edition entitled, Tactical Guns and Gear. His conclusion referred to Joe Citizen and the requirement that he ought be able to effectively operate an M16.

    Here is why I think you get his intended audience wrong: "And frankly, if you are only attaching a simple weapon light to your carbine, a piece of Picatinny rail bolted onto your handguard works well. Picatinny-rail-system handguards came from the need to bolt on an IR laser (such as the ITI US GI-issued PEQ-2 unit) and have it retain zero. If this is not a requirement of your AR-15-style carbine, I would think long and hard before getting your rail system. Ask yourself whether you are getting it because you really need it or because you think it looks cool."

    Few, if any, of we CIVY's have an AN/PEQ-2A (or equivalent.) So, to whom is he addressing this comment? The same audience as the audience of the whole article? I think so.

    Zak Smith had a good article on slings. Someone named Patrick Sweeney had a couple of articles. I didn't note any bio info on him at the end of the articles. Who is he?
    Maybe he is talking too two audiences (don't know). Oh, I am a civy and have NV and IR lasers.




    C4

  8. #28
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    I have that magazine and will go back and read the article. Maybe if it isnt to much of a PITA I might scan it and post it up here.
    Love you Pop. F*ck Cancer.

  9. #29
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    Quote Originally Posted by Submariner
    Someone named Patrick Sweeney had a couple of articles. I didn't note any bio info on him at the end of the articles. Who is he?
    Patrick is a well known gunsmith. He also (as you see) writes for magazines and whatever they call the web stuff, ezines or whatever
    Please let me know if I have offended you...
    I would like to move on to my next task.


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  10. #30
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    I bought the magazine pretty much for that article, although it has some other interesting articles. Simplicity and irons permanently set to cowitness were some of the points made. Once I establish the credibility of the sources, I pretty much get my info from sites like this and 10-8 and have pretty much kissed gunzines goddbye. I will buy one for a name that I like or if it has four or five interesting articles. If you use the search function, you find that most of the questions have been asked.

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