Page 9 of 10 FirstFirst ... 78910 LastLast
Results 81 to 90 of 91

Thread: Carbine vs Mid

  1. #81
    Join Date
    Mar 2010
    Location
    Maine
    Posts
    7,868
    Feedback Score
    0
    Quote Originally Posted by bp7178 View Post
    I wouldn't dispute this, but how significant of a difference is it?

    If low pressure was ideal, we would all use rifle gas systems.
    Dwell time issues on 14.5'' and 16.1''.

    If people could do it reliably I bet we'd see rifle gas 14.5'' guns tomorrow.
    We miss you, AC.
    We miss you, ToddG.

  2. #82
    Join Date
    Nov 2010
    Location
    MI
    Posts
    3,055
    Feedback Score
    21 (100%)
    Everything is a balancing act.

    For best extraction, you want to have the chamber pressure as low as possible. This implies a long gas port location.

    In order to cycle the action, you need a particular amount of gas impulse. This is pressure x time. Time that the piston is under pressure is related to the distance from the gas port to the muzzle. More time implies a short gas port location or a long barrel.

    Pressure in the gas system is related to the available chamber pressure and the gas port size.

    The rifle length system extracts well under low chamber pressures, but requires a 20" barrel.

    The carbine system suffers from early extraction and high gas port pressures but works well with barrels as short as 10"-12".

    The midlength system splits the difference and works well with 14-16" barrels.
    Black River Tactical
    BRT OPTIMUM HFCL Barrels - Hammer Forged Chrome Lined 11.5", 12.5", 14.5"
    BRT OPTIMUM Barrels - 16" MPR, 14.5" MPC, 12.5" MRC, 11.5" CQB, 9" PDW
    BRT EZTUNE Preset Gas Tubes - CAR and MID
    BRT Covert Comps 7.62, 5.56, 6X, 9mm
    BRT MarkBlue Gas Tubes - BRT EXT, EXC and PDW Lengths
    BRT MicroPin Gas Blocks - .750" & .625"
    BRT MicroTUNE Adjustable Gas Blocks
    BRT CustomTUNE Gas Ports

  3. #83
    Join Date
    Apr 2010
    Location
    Phoenix, Az
    Posts
    3,347
    Feedback Score
    1 (100%)
    Is a carbine system going to be more reliable with cheap low powered .223 that might short stroke a middy? Serious question.
    C co 1/30th Infantry Regiment
    3rd Brigade 3rd Infantry Division
    2002-2006
    OIF 1 and 3

    IraqGunz:
    No dude is going to get shot in the chest at 300 yards and look down and say "What is that, a 3 MOA group?"

  4. #84
    Join Date
    Sep 2007
    Posts
    1,306
    Feedback Score
    0
    these carbine vs mid threads are always an example of how poor the ar15 system is mechanically.

    There's only 3 things we can manipulate on a 223/5.56mm ar15 for best performance.

    1. gas port location

    2. extractor tension.

    3. 5.56mm NATO chamber.

    Some things we can't change in the 223/5.56mm ar15 system is....

    1. extractor circumference

    2. weak rim on 223/5.56mm casing

    3. poor taper on 223/5.56mm casing

    4. lack of primary extraction on ar15 system

  5. #85
    Join Date
    Jun 2006
    Posts
    6,028
    Feedback Score
    13 (100%)
    Quote Originally Posted by kal View Post
    these carbine vs mid threads are always an example of how poor the ar15 system is mechanically
    I just don't see it.

  6. #86
    Join Date
    Sep 2009
    Location
    South La.
    Posts
    1,892
    Feedback Score
    9 (100%)
    Quote Originally Posted by kal View Post
    these carbine vs mid threads are always an example of how poor the ar15 system is mechanically.

    There's only 3 things we can manipulate on a 223/5.56mm ar15 for best performance.
    1. gas port location
    2. extractor tension.
    3. 5.56mm NATO chamber.

    Some things we can't change in the 223/5.56mm ar15 system is....
    1. extractor circumference
    2. weak rim on 223/5.56mm casing
    3. poor taper on 223/5.56mm casing
    4. lack of primary extraction on ar15 system
    =============================

    What about also "manipulating" :
    1. gas port size
    2. buffer weight
    3. ??

    .

  7. #87
    Join Date
    Sep 2007
    Posts
    1,306
    Feedback Score
    0
    What about also "manipulating" :
    1. gas port size
    2. buffer weight
    Yes the port size and buffer weight can definitely be changed for a desired result.

    The reason I didn't mention gas port size is because of the possibility of erosion indifference. Meaning, although an M4 barrel can be manufactured with a smaller gas port diameter, it will only delay the erosion process and will eventually end up as worn out as a regular M4 barrel gas port but with more rounds through.

    I have no way of proving this and that's why I left it out. But the idea is that the size of the port will not decrease the violent abrasion/pressure of hot gas closer to the chamber as opposed to a gas port drilled closer to the muzzle of the same barrel length.

    I left out buffer weight because I figured increasing the gas system length would be a better permanent solution. This would be purely opinion at this point.

  8. #88
    Join Date
    Oct 2010
    Location
    Denver-ish, CO, USA
    Posts
    77
    Feedback Score
    0
    I've only owned middies until recently. Honestly, when I picked up my first one, I simply preferred the look of the middies on a 16" barrel.

    Now that I have a carbine length, I prefer the increased real estate and longer site radius of the mids.

    If I had started with carbines, I don't think I'd spend the cash to replace them with mid-lengths unless someone could show me a controlled study showing significant reliability improvements, but I don't expect to buy carbine length gas unless I'm getting a shorty.

  9. #89
    Join Date
    Sep 2009
    Location
    Sopines, NC
    Posts
    1,759
    Feedback Score
    52 (100%)
    Quote Originally Posted by ucrt View Post
    =============================

    What about also "manipulating" :
    1. gas port size
    2. buffer weight
    3. ??

    .
    4. Dwell time (for example LMT enhanced carrier)
    5. Buffer spring rate
    6. Buffer tube length
    7. Carrier gas venting
    8. Gas tube length and volume
    9. BCG weight
    10. Bullet weight and powder charge
    11. Muzzle device/ suppressor

  10. #90
    Join Date
    Sep 2007
    Posts
    1,306
    Feedback Score
    0
    4. Dwell time (for example LMT enhanced carrier)
    I would love hard evidence that proves a tiny bit of more space on the camming track is going to significantly increase extraction reliability for high pressure 5.56mm nato ammo, as well as 223 steel cased ammo in various 14.5/16" carbine/mid-length systems, assuming everything else is untouched.

Page 9 of 10 FirstFirst ... 78910 LastLast

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •