OAL for a Douglas Air Gauge .300 win mag

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by MN Rifleman, Jul 7, 2013.

  1. MN Rifleman

    MN Rifleman New Member

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    Hi all. last fall i had a new barrel put on my .300 by a local gunsmith. i wanted a good solid, accurate barrel, and he only used douglas barrels, so he said an air gauge, 5 contour would be good. so i got the gun, and started handloading for it. i measure the chambers oal by seating a bullet down with the bolt. with a 175 grain Barnes LRX, i had a chamber OAL of 3.607. now that seems long to me from what ive read. a sierra Match King 175 gr. has a oal length of 3.530. all with trimmed brass. should i be concerned with this OAL? this an older rifle, 6 digit serial rem 700. maybe they meant for heavier bullets to be used in the barrel? the rifle doesnt honestly shoot that good with the Barnes LRX. im on the look for bullets that will shoot. i want to use lead free. i struggle to get sub MOA groups at 100 yet i can get my SD down under 10 in a 3 shot group. so im just not sure what to make of that. any advice would be great thanks.
     
  2. 375fan

    375fan Well-Known Member

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    What is twist rate of barrel? Barnes has twist rate recommendations for their bullets. In my 300winmags have 1-10 twist which handle the Barnes just fine.
    Judging by your oal, your seating bullets so that ogive of bullet is touching lands, correct?
    In my experience with Barnes x/tsx/ttsx bullets they like a little jump and not seated against the lands.
     

  3. benchracer

    benchracer Well-Known Member

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    Base to tip OAL will vary with bullet length and shape. Different bullets will contact the rifling at different lengths. A monometal bullet like the Barnes will be longer for a given weight because copper is less dense than lead.

    Have you tested for seating depth? Barnes recommends seating their bullets .030 to .70 from the rifling.

    Now that you know your length to the rifling, back the bullet off and load 3 or 5 shot groups at the following depths: .030, .050, .070 from the rifling. Shoot them in round robin fashion. One of the groups will likely shoot better than the others. Use that seating depth to do your powder charge workup. Fine tune your seating depth, if desired.

    When you are finished with that process, you should have a load that shoots as well as it is going to with the combination of components you are using.
     
  4. MN Rifleman

    MN Rifleman New Member

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    yea sorry I forgot to mention that ive tested these bullets and they like a 30 thousands jump to the lands. I tested all the way up to 70 thousands jump but I didn't get much difference in groups, but 30 off seemed to work the best. and yes my barrel is a 1-10 twist. im still seated at 3.577 and that's still kinda long. im just wondering if that's ok? or do other folks have douglas barrels and have seen this?
     
    Last edited: Jul 8, 2013
  5. benchracer

    benchracer Well-Known Member

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    More details about your components (primer, powder, brass) and powder charge workup would be useful here.
     
  6. RT2506

    RT2506 Well-Known Member

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    I have asked a number of GOOD gunsmiths which barrel is the best. On average I have been told to flip a coin. You can get a good barrel from any of them but sometimes even a barrel that looks good will not shoot. Sometimes it is not the barrel that is the problem Bedding of the action. The action itself may not be square. You might not have found THE LOAD yet. Some barrels don't like mono bullets. I have had something as simple as changing the primer brand turn a so so shooter in to a bug hole shooter. It's a crap shoot. :D
     
  7. MN Rifleman

    MN Rifleman New Member

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    Remington brass, neck sized fired in my chamber, federal magnum primers, used magpro powder upto 83.5 grains, used h4831sc at 74.5 grains max, and haven't played much with imr 7828 but shot some at 74 grains. Magpro is throwing the 175 lrx at 3250 fps or so, and that shot the best. Little too hot though. I have imr 7828 ssc to try. I'm also gonna try some match kings to see if they shoot better. Maybe the barrel don't like all copper. Also gonna try some 168 Barnes ttsx to try.
     
    Last edited: Jul 8, 2013
  8. artemistrad

    artemistrad Member

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    Hi,
    I have the same problem. The LRX 175gr is very sleek and long. My bullets have a bulletjump of 0.144" in the 300winmag, otherwise they won't fit the magazine anymore. I load 80gr H1000 behind them and Fed 215M gold medal primers. No pressure signs and 0.35" groups on 110yrds from a standard barrel 26" and 1:10twist.