200gr Accubond, Retumbo, and 300 Win Mag

Discussion in 'Reloading' started by 4th_point, Jul 24, 2010.

  1. 4th_point

    4th_point Well-Known Member

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    Nov 22, 2008
    I didn't find much realworld data for 200gr bullets and Retumbo so I figured this might help someone whose also looking into these components for the 300 Win Mag. I'm not really looking for advice, but just want to share what I found with my rifle. I've posted this at a couple of the forums I frequent.

    Note that the Tikka has a decent amount of freebore when loaded to SAAMI COAL.

    Tikka T3, 300 Win Mag, 24" barrel
    -200gr Accubond
    -new Rem cases (plain not nickel)
    -CCI LR magnum primers
    -3.35" COAL (fits mag)
    -0.002" neck tension
    -Retumbo
    -Chrony Alpha

    76gr ---> 2580fps (73gr is Hodgdon starting load)

    78gr ---> 2658fps (this is Hodgdon MAX LOAD)

    80gr ---> 2800 fps (EXCEEDS Hodgdon MAX LOAD by 2gr)

    Note that Hodgdon lists the start load at 73gr (2703 fps) and max load at 78gr (2872 fps). I think they recently revised the velocity figures because I recall the 78gr load giving close to 3000 fps on their website just a week or two ago.

    I started at 73gr and worked slowly to 80gr. I didn't include all the data to save time typing. Bolt lift and extraction were easy with all loads.

    At 79-80gr, the primers just barely show signs of cratering. Factory 180gr Core-lokts show more cratering than the 80gr load above. No signs of primer flattening.

    Recoil is very mild with the above Retumbo loads. Factory Core-lokts seem to have much more recoil, and higher recoil velocity. These Retumbo loads feel more like a 30-06 than a 300 magnumb.

    Case necks 'seemed' more smoked with less than 79gr. At 79gr and above, the necks appear cleaner but still have some residue.

    Note that above 78gr, the load is highly compressed(crunch). I used a funnel and weighed each charge. I did not use an extended drop tube.

    I don't recommend that anyone try these loads without working up slowly. 80gr is a lot of powder at 3.35" COAL, but the rifle has a quite a bit of freebore. Velocity is reasonable, but I have no idea what the pressure is.

    Some may wonder if my rifle shoots slow. I have shot the factory 180gr Core-lokts at 2965fps. Remington advertises these at 2960fps so I think this particular rifle is within the normal range. And my chronograph appears to be functioning fine.

    Jason
     
    Last edited: Jul 24, 2010