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Thread: Ruger SR-556

  1. #181
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    Elaborate please.

    Quote Originally Posted by C4IGrant View Post
    This weapon has major issues so I would avoid it.

    The weapon is also going to be VERY heavy.
    C4
    What are its major issues? I haven't seen any reviews of the gun outside of the usual "gun rags". What do you know? Spill it.

    Regarding its weight, it's 7.92 lbs w/o magazine compared to the LMT MRP 16" piston at 7.3 lbs and 7.85 lb for the HK-416 16". I don't see this as being out of line with competition in the market; or do you think all pistons are VERY heavy?
    Last edited by nogoodnamesleft; 06-05-09 at 17:53. Reason: grammar police.

  2. #182
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    Quote Originally Posted by nogoodnamesleft View Post
    What are its major issues? I haven't seen any reviews of the gun outside of the usual "gun rags". What do you know? Spill it.

    Regarding its weight, it's 7.92 lbs w/o magazine compared to the LMT MRP 16" piston at 7.3 lbs and 7.85 lb for the HK-416 16". I don't see this as being out of line with competition in the market; or do you think all pistons are VERY heavy?
    The piston system has issues that I cannot go into. Let's just say that I would not be one of the first buyers.

    The MRP and HK 416 are classified as heavy (FYI) and yes, I classify almost all pistons as heavy.

    The reason why most all piston guns are heavy is because they have to use very heavy barrels to keep the movement down. This is why piston guns (once hot) shoot poor groups.


    C4
    Last edited by C4IGrant; 06-05-09 at 18:03.

  3. #183
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    Quote Originally Posted by C4IGrant View Post
    The reason why most all piston guns are heavy is because they have to use very heavy barrels to keep the movement down. This is why piston guns (once hot) shoot poor groups.
    C4
    That doesn't seem to quite follow. Heavier barrels are known for better accuracy and are better at dissipating heat (larger surface area [Area = pi*r^2*length for a cylinder]). Indeed, aren't machine gun barrels heavier for that very reason -- to dissipate heat?

  4. #184
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    Quote Originally Posted by nogoodnamesleft View Post
    That doesn't seem to quite follow. Heavier barrels are known for better accuracy and are better at dissipating heat (larger surface area [Area = pi*r^2*length for a cylinder]). Indeed, aren't machine gun barrels heavier for that very reason -- to dissipate heat?
    Heavy barrels (on machine guns) help with warping. We are not talking about a machine gun though.


    C4

  5. #185
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    Quote Originally Posted by nogoodnamesleft View Post
    That doesn't seem to quite follow. Heavier barrels are known for better accuracy and are better at dissipating heat (larger surface area [Area = pi*r^2*length for a cylinder]). Indeed, aren't machine gun barrels heavier for that very reason -- to dissipate heat?
    I think he's saying that they have to be made heavier, to increase rigidity, to dampen the movement of the barrel due to forces applied by the operating system.

    Also, your equation is for the volume of a cylinder. Surface area would be pi*2*r*L. I'd have to brush up on my heat transfer to confirm this, but note that the volume increases exponentially with increasing radius, but surface area only linearly. This means you're adding mass (and capacity to retain heat) faster than surface area to cool it. To effectively add surface area you really need aggressive "texturing" like annular fins. It's not that that heavier barrels dissipate heat quicker, but they do take longer to heat up and are more rigid at high temps than an otherwise identical but thinner profile.
    --Josh H.
    Zombies seek out and eat brains. Don't worry; you'll be safe if they attack.

  6. #186
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    Quote Originally Posted by LOKNLOD View Post
    I think he's saying that they have to be made heavier, to increase rigidity, to dampen the movement of the barrel due to forces applied by the operating system.

    Also, your equation is for the volume of a cylinder. Surface area would be pi*2*r*L. I'd have to brush up on my heat transfer to confirm this, but note that the volume increases exponentially with increasing radius, but surface area only linearly. This means you're adding mass (and capacity to retain heat) faster than surface area to cool it. To effectively add surface area you really need aggressive "texturing" like annular fins. It's not that that heavier barrels dissipate heat quicker, but they do take longer to heat up and are more rigid at high temps than an otherwise identical but thinner profile.
    DING! DING! DING! We have a WINNER!


    C4

  7. #187
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    Quote Originally Posted by C4IGrant View Post
    DING! DING! DING! We have a WINNER!


    C4
    What do I win? I'll take that TR24 between the Kewpie doll and the stuffed bear!


    To take this on a tangent, but a technical one, I can't help but wonder if our insistence on "free floating" AR barrels isn't actually a detriment to accuracy on the piston systems. Sure, it succeeds in isolating the barrel from outside forces via grips, slings, weight from accessories, bipods, etc. but it also leaves the barrel at the mercy of forces of the operating system.

    I wonder if something like an LMT MRP piston system but with the gas block affixed in the end of the rail via some sort of "bushing" would have a further negative or positive effect on accuracy... Think of the monolithic rail forming a sort of superstructure to support the barrel, which could then perhaps be made a little lighter in weight.

    Or I could be way off base with that. Might make an interesting experiment...
    --Josh H.
    Zombies seek out and eat brains. Don't worry; you'll be safe if they attack.

  8. #188
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    Quote Originally Posted by LOKNLOD View Post
    What do I win? I'll take that TR24 between the Kewpie doll and the stuffed bear!


    To take this on a tangent, but a technical one, I can't help but wonder if our insistence on "free floating" AR barrels isn't actually a detriment to accuracy on the piston systems. Sure, it succeeds in isolating the barrel from outside forces via grips, slings, weight from accessories, bipods, etc. but it also leaves the barrel at the mercy of forces of the operating system.

    I wonder if something like an LMT MRP piston system but with the gas block affixed in the end of the rail via some sort of "bushing" would have a further negative or positive effect on accuracy... Think of the monolithic rail forming a sort of superstructure to support the barrel, which could then perhaps be made a little lighter in weight.

    Or I could be way off base with that. Might make an interesting experiment...
    I believe that the Ruger is NONE free floating.


    C4

  9. #189
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    Quote Originally Posted by C4IGrant View Post
    The piston system has issues that I cannot go into. Let's just say that I would not be one of the first buyers.

    The MRP and HK 416 are classified as heavy (FYI) and yes, I classify almost all pistons as heavy.

    The reason why most all piston guns are heavy is because they have to use very heavy barrels to keep the movement down. This is why piston guns (once hot) shoot poor groups.


    C4
    The LMT Piston barrel isn't any heavier than their DI barrel, is it? But yes, I agree, the LMT isn't the lightest gun. I'm thinking of running my next class with a light M4 just to compare.

  10. #190
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    Quote Originally Posted by LOKNLOD View Post
    I think he's saying that they have to be made heavier, to increase rigidity, to dampen the movement of the barrel due to forces applied by the operating system.

    Also, your equation is for the volume of a cylinder. Surface area would be pi*2*r*L. I'd have to brush up on my heat transfer to confirm this, but note that the volume increases exponentially with increasing radius, but surface area only linearly. This means you're adding mass (and capacity to retain heat) faster than surface area to cool it. To effectively add surface area you really need aggressive "texturing" like annular fins. It's not that that heavier barrels dissipate heat quicker, but they do take longer to heat up and are more rigid at high temps than an otherwise identical but thinner profile.
    No, not the volume -- you're correct -- my mistake for using 'r^2' instead of 'r*2' when defining 'Area' (brain fart).
    But I did mean the surface area of the cylinder, which does increase with a larger radius in a linear fashion, so the point still stands. Larger barrels (i.e. increased diameter) do dissipate more heat than do thinner profiled barrels in a given amount of time due to increased surface area. And yes, the increase in barrel mass does increase at a faster rate than surface area, but given a similar number of rounds then a similar amount of heat is transferred to each barrel. The larger barrel will not get as hot and will dissipate that heat at greater rate than a thinner barrel. I would expect that the thicker barrel would always provide better groups than the thinner barrel given similar round counts (obviously ignoring all other factors).

    I agree with the comments about aggressive "texturing" and rigidity.

    Or is it the mechanical influence of the reciprocating mass in combination with a less rigid, hot barrel your referring to? And if so, how hot do these barrels get at which this occurs? I wouldn't think we're anywhere near the temperatures required for the barrels' steel to exhibit such behavior.

    I do think that a piston ,in general, would give worse groups from the start (i.e. cold barrel) due to the reciprocating mass, but heating would not really be much of discriminator in group size. Could be wrong, but that's why I'm asking. Hmmmmmmm.......

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