300 weatherby varing velocity

Discussion in 'Reloading' started by huntaway, Oct 24, 2009.

  1. huntaway

    huntaway New Member

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    Sep 24, 2009
    300 weatherby velocity variations
    Does any one have any experiance with the Weatherby mark V Ultra light with the Krieger bbl. I cronographed mine today and it is a lot faster than my older Japanese Mark V. 40*F @ 1400 feet with 84 grains 7828ssc and 180gr nosler accubonds produced 3200fps with old rifle and 3325 to 3350 ultra light. Same ammo in both rifles. Thats considerably faster than the load data show.
    Does it have anything to do with the Kreiger kriterion barrel?
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  2. MagnumManiac

    MagnumManiac Well-Known Member

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    Feb 25, 2008
    It may just be that you have a tighter chamber and bore than your previous rifle which will increase pressure and therefore velocity.
    It may even have a minimum chamber, which is good for case life!

    I had a 300Weatherby on a Win Mod70 S/S that would get 3400fps with 180gr bullets even though the same rounds would only get 3300fps in a friends rifle, BTW, this was with factory Weatherby ammo.
    Mine had a very tight chamber and bore, the freebore length was normal though.
    gun)
     

  3. MontanaRifleman

    MontanaRifleman Well-Known Member

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    May 21, 2008
    It may be a couple of things... It could be the chamber like Magnum Maniac said and/or the barrel. Every rifle/chamber/barrel will be different, some more than others.

    It could also be (and/or) the chrony. I have seen chrony velocites change drastically in the same load as lighting changes, especially when going into a shodow. Most of the chrony's we use are not precise instruments. I bought a second chrony to test agains my first one and they varries in velocity anywhere from 10-50 fps set up one in front of the other. For that reason, I just use chrony's as ballpark guide and use drops and verticle POI differences to determine true velocity/BC and load consistancy.

    Mark