Which one to use? (chrono data)

Discussion in 'Caliber Corner' started by ABNAK, Apr 15, 2012.

  1. ABNAK

    ABNAK

    Messages:
    731
    Likes Received:
    7
    Joined:
    Apr 22, 2005
    Location:
    Tennessee
    Bought a new Kahr CM9 with a 3" barrel. Chrono'd some HST loads and was wondering which GT members would recommend. Five rounds of each.

    147gr +P HST: 939fps average

    124gr +P HST: 1110fps average

    What is the expansion threshhold for the 147gr HST? Wonder if 939fps is enough (?). Same for the 124gr +P.
     
  2. cowboy1964

    cowboy1964

    Messages:
    30,746
    Likes Received:
    17,640
    Joined:
    Sep 4, 2009
    Location:
    U.S.A.
    I'd go with the 124+P personally. Much easier to find generally too.

    23 grains more weight or 180 more fps. I choose the velocity.

    I believe the expansion threshold is pretty low. Probably around 700-800 fps.
     
    Last edited: Apr 15, 2012

  3. Glock19Fan

    Glock19Fan Cool Guy

    Messages:
    1,729
    Likes Received:
    9
    Joined:
    Mar 25, 2003
    Location:
    Tennessee
    If the 147 grain +P uses the same bullet as the standard pressure loading, I would go with that. 939 FPS is just around 50 FPS away from what you would expect from a standard pressure round from a standard barrel length, while the 124 loading is almost 100.
     
  4. PghJim

    PghJim

    Messages:
    1,988
    Likes Received:
    93
    Joined:
    Apr 21, 2005
    Location:
    Pittsburgh
    There is another thread where I tested Underwood 124gr GD +P+ against Speer factory 124gr GD +p. I was getting the same velocity out of my Kahr PM9 (3") with the Underwood ammo as I was getting from the Speer factory +p out of a 4.5" barrel, about 1,230fps. My PM9 is now packed with the Underwood 124gr GD +p+. Recoil is not that bad.
     
  5. ABNAK

    ABNAK

    Messages:
    731
    Likes Received:
    7
    Joined:
    Apr 22, 2005
    Location:
    Tennessee

    The PM9 has a polygonal barrel; the CM9, being the "budget" model, has a regular land-and-groove barrel. That *may* account for the better performance from your PM9.
     
  6. hotpig

    hotpig IAFF Local 4766 CLM

    Messages:
    2,630
    Likes Received:
    10
    Joined:
    Dec 1, 2000
    Location:
    SW / West Central Illinois
    When talking about the modern ammo they are made to function in low velocity 3'' guns. Other than maybe a slight loss in penetration with speed the bullet does not care if it is flying at 800fps or 1200fps.
     
  7. 9mm +p+

    9mm +p+

    Messages:
    1,891
    Likes Received:
    249
    Joined:
    Mar 1, 2005
    Location:
    Old Dominion
    124 no question, I wouldn't run a 147 in any 9 of mine and don't.
     
  8. ABNAK

    ABNAK

    Messages:
    731
    Likes Received:
    7
    Joined:
    Apr 22, 2005
    Location:
    Tennessee
    The 147gr +P HST is my carry load in my Glock 19 (1021fps average out of it). I've only recently become a convert to the "heavy for caliber" side of things what with the advent of new bullet designs that blow away stuff from the 1990's. That said I'm inclined to lean towards the 124gr +P HST for the Kahr's little 3" pipe; I trust the modern 147gr HST design when I'm getting >1000fps but that 900'ish velocity makes me leery (maybe a throwback to the "old days" of mistrusting 147gr altogether?).

    And yeah, I took note of what Hotpig said. Just a gut feeling, not based in fact.
     
  9. WiskyT

    WiskyT Malcontent

    Messages:
    11,682
    Likes Received:
    14
    Joined:
    Jun 12, 2002
    Location:
    North Carolina
    Hot Pig isn't alone. Winchester specifically recommends 147's for short barrels because they loose the least amount of velocity. I found the same thing clocking rounds out of my LC9, the Ranger 147's loose very little from the short barrel. The 124's aren't going much faster than the 147's when you get right down to it out of the ammo I clocked. Also, the 147's are designed to work at 9xxfps.