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Thread: Stainless vs. 4150 (Barrel)

  1. #21
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    Even with the increased leade, the effective case capacity difference between the 223 and 5.56 is small and very little, if any, velocity difference will be seen between the two when used in their respective chambers.
    If I look at Barnes' website and reference their reloading info, listing the same powder and bullet, the 5.56 has maybe 3-4 grains more powder and hits a velocity almost 200 FPS faster.

    I agree that the pressure of the shot, .223 round in a .223 chamber vs a 5.56 round in a 5.56 chamber is the same, the 5.56 has a higher velocity. It's common knowledge that a 5.56 round in a .223 chamber can lead to dangerous pressure levels.

    I just haven't seen any data to suggest a .223 round from a .223 chamber hits the same velocity as a 5.56 from a 5.56 chamber.

  2. #22
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    Quote Originally Posted by bp7178 View Post
    If I look at Barnes' website and reference their reloading info, listing the same powder and bullet, the 5.56 has maybe 3-4 grains more powder and hits a velocity almost 200 FPS faster.

    I agree that the pressure of the shot, .223 round in a .223 chamber vs a 5.56 round in a 5.56 chamber is the same, the 5.56 has a higher velocity. It's common knowledge that a 5.56 round in a .223 chamber can lead to dangerous pressure levels.

    I just haven't seen any data to suggest a .223 round from a .223 chamber hits the same velocity as a 5.56 from a 5.56 chamber.
    You are correct. While the 5.56 does sometimes have greater velocities, loading data has variances form source to source. That's why I say "similar" velocities and pressures. It not always possible to make direct comparisons.

    Sierra lists two sets of data, one for the 223 AR (20" bbl), another for the 223 bolt action (24" bbl). Of course the longer barrel produces more velocity, but the interesting thing is, when using H335, up to 2 grains more powder can be used in the bolt action than the AR. They do not specify which chambers are used which does nothing to clarify things. Further adding to the confusion is the use of chambers such as the 223 Wylde. I have no proof, but I suspect more manufacturer's are making their sporting 223 chambers closer to Wylde specifications than SAMMI.

    Still, the evidence points to the fact that 223 loads when fired in true 223 chambers produces similar pressures to 5.56 loads being fired in 5.56 chambers
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  3. #23
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    Looks like PSA copied and pasted something wrong. Noveske did chrome some SS barrels, but said that the costs far outweighed the benefits and that they were very expensive. I seriously doubt that this is a chrome-lined SS barrel.

  4. #24
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    Noveske also made a barrel out of 17-4 stainless if memory serves. Very very hard material, and the barrels were a small fortune.

    Test barrels don't have gas ports, and you'll always lose some velocity in an AR15 as compared to a bolt action. There's no unlocking with a bolt action, well, not at the timing that exists in an AR15. I speculate this is why you can get away with more in a .223 bolt gun.

    Still, the evidence points to the fact that 223 loads when fired in true 223 chambers produces similar pressures to 5.56 loads being fired in 5.56 chambers
    I agree with that, but 5.56 loads are generally 200 FPS faster.

    I think we're losing each other on use of the terms pressure and velocity.

    My understanding of a cartridge being fired is that the hammer will strike the primer, the load will shift forward until the bullet hits the lands and groves, and the powder begins to burn. It doesn't explode per se, but gradually burns. All of this happens in the matter of a few milliseconds, and the bullet is accelerated to 2,200-3,000+ FPS. The longer freebore of the 5.56 in essence give a larger volume of space for the powder to begin it's burn after the primer detonates.

    I with you that the pressure is the same, but the 5.56 round/chamber will result in more velocity delivered to the projectile.

    I haven't seen chronograph testing where .223 spec loads are at 5.56 velocities when fired from .223 chambers.

    From a precision standpoint, the 5.56 rounds generally aren't the most accurate at 100 yards.
    Last edited by bp7178; 09-11-11 at 13:16.

  5. #25
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    Lots of these SS barrels also advertise a Wylde chamber. I know what they claim, but what has been the experience? Thanks.

  6. #26
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    Quote Originally Posted by m4brian View Post
    Lots of these SS barrels also advertise a Wylde chamber. I know what they claim, but what has been the experience? Thanks.
    I asked a similar question in another thread. Here it is along with an answer:


    Quote Originally Posted by justin_247 View Post
    This seems like the opportune time to ask this question...

    The LaRue, WOA, Rainier, and Compass Lake offerings all have Wylde chambers, however I've heard that Wylde chambers may be too tight for true 5.56 ammo, such as MK262, and this is what causes many failures to extract on RRA rifles. This is why Noveske came up with their NMm0 chambers in the first place.

    Is this simply a myth, or is it a legitimate problem? If it is legitimate, I would stick to the Noveske, Centurion, and BCM offerings.
    Quote Originally Posted by Robb Jensen View Post
    Once in a great great while I see guns with .223 Wylde chambers have issues with 5.56mm NATO ammo. They shoot .223Rem and 5.56mm NATO a little more accurately than 5.56mm NATO chambers.

    I have had no issues shooting 5.56mm NATO ammo out of BCMs SS410 barrels with their USMC SAM-R chamber.
    Quote Originally Posted by justin_247 View Post
    Very interesting! Just for my own education, may I ask what the difference is between the SAM-R and 5.56 chambers are in comparison to the Wylde?
    Quote Originally Posted by Robb Jensen View Post
    SAM-R is the USMCs version of the .223 Wylde. I have many more rounds through Wylde chambers FWIW. Both are tighter in the neck and throat.
    If one will ever use the gun heavily suppressed I'd suggest getting a 5.56mm NATO chamber.
    Quote Originally Posted by dakotalawdog View Post
    I would suggest the BCM 16" SS410 barrel. The SAM-R chamber is like a Wylde chamber, but should be more reliable with 5.56 ammo. I bought a 20" recently and its shooting 3/4MOA or better at 200 yards with match ammo. The 16" should give you similar results, and it is by far the best value out there. You can spend the extra money and buy a Krieger, but trust me, you're not getting anything better than you would with the BCM. http://m4carbine.net/showthread.php?t=71240

    As much as you want it to be a dual purpose gun, make it a duty gun first. It should be reliable, lightweight and accurate. The 16" BCM barrel will give you all three.

  7. #27
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    Quote Originally Posted by bp7178 View Post
    I agree with that, but 5.56 loads are generally 200 FPS faster.

    I think we're losing each other on use of the terms pressure and velocity.
    I am in agreement with what you said. To clarify, let me explain that under the circumstances, 200 fps difference between two different rifles is close enough to be similar, in my book
    Last edited by MistWolf; 09-11-11 at 16:15.
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