Slow barrel

Discussion in 'Reloading' started by chain, Oct 21, 2007.

  1. chain

    chain Well-Known Member

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    Dec 28, 2004
    The barrel on my 300 win produces 100-150 fps than posted velocities in the manuals. I had a load for 200 gr Accubonds that was a couple grains shy of max but grouped well. I was concerned however about their velocity having not chronoed them yet. As a back up plan I took some 180 Accuubonds to the range loaded with the max of Rl 22. The 2oo's shot well but were only 2750fps the 180's didn't shoot real bad around 1" a little less but they were in the high 2900's . The funny thing is the 180 groups didn't get much bigger at 250-275 yds and the 200's opened proportionately or a little more. I am going to shoot the 180's, I might try some H-1000 and see what that gives me for velocity but I have found that RL 22 seems to be the fastest. What do you guys think? Mule deer and maybe a cow elk this year is what it will be used for. Thanks
     
  2. J E Custom

    J E Custom Well-Known Member

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    Jul 29, 2004
    Chain

    It could be a million things that cause your load to appear slower than
    the listed loads,Here are some.

    Barrel length could be different than test barrel .
    Chamber could be different.
    Different brass than in test barrel.
    Also reloading books use calculated velocites most of the time instead
    of actual test barrels as in the past before computer software.

    Some factory barrels are very rough inside and can not match the hand
    lapped custom barrels velocity( I recently lapped a winchester in 25 WSSM
    that was very bad and would not group and it increased the velocity by
    152 ft/sec and reduced group size 300%.

    A Bad'ly fouled barrel will also reduce velocity.

    One more thing could be the chronograph. (If a frend has one check velocity
    in theirs and compair to your readings.

    Velocity is not everthing so dont worry to much about it as long as there is
    enough to do the job at the distance you will hunt.

    I hope this will help
    J E CUSTOM
     

  3. chain

    chain Well-Known Member

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    Dec 28, 2004
    Roger that. I cleaned the barrel better than normal this time so I will see on Sat. how it is. I am close enough to where I wanted to be, I just want to get an accurate reading now to set up range card for new bullets. Thanks
     
  4. 41mag

    41mag Well-Known Member

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    Chain,

    What your seeing is not that uncommon when develoing loads. I have seen it go both ways above and below what book velocities are using similar printed loads.

    I generally use them as a guide and look for spikes while approaching them. If I have noticed nothing out of the ordinary I work for accuracy around the velocity range I am seeking. If I hit something that groups out well even if below printed velocities I will usually note it and then work up a bit more looking for pressures. If I hit pressure I will back down and be happy or switch to a different powder.

    I have a Ruger 77 which shoots every load I have including factory around 300 - 450fps below anything listed on ammo boxes or printed in manuals for a given load. I thought the barrel was shot but it has been scoped and other than a little curd being built up, it was in great shape. My only solution was to continue to work up until I hit pressure signs with it, and this was almost 3 - 4 grs above anything the manuals listed. Now my loads are shooting to listed velocities for the bullet weights and still not hitting max.

    If I were you and had a good load, I would shoot it and continue to look at similar or possibly just a tad quicker burn rate to try out another load with. I know that there are better powders out there for the purpose, but I got better velocities and accuracy from RL-19 out of my 7 mag than any other powder I tried using 162gr Hornady bullets. The best part of that load was being able to drop down to the 154gr SST and not having to change anything with it.
     
  5. chain

    chain Well-Known Member

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    I was messing around with soem RL 22 and just wasn't making the velocities posted. I looked at the ballistics tables and started making a drop chart for that load and just decided to go back to an H-1000 load I used before. It is better to be accurate than fast. Thanks
     
  6. X-man

    X-man Well-Known Member

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    May 4, 2007
    Chain

    Have you tried carefully increasing the powder charge (while watching for pressure signs)?
    I suspect you have an overly large chamber and need to increase your powder charge to componsate.

    Not knocking H-1000, but Rl-22 is normally a very good 300 Win powder (at normal ranges). Way out there H-1000 does offer a few advantages.