is there substantial gain with a 7-300wsm over 7wsm

Discussion in 'Long Range Hunting & Shooting' started by clemens, Jul 21, 2012.

  1. clemens

    clemens Well-Known Member

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    Seen a lot of threads with the 7-300wsm was wondering is there a major gain over the 7wsm. or is there? seems to be a really good cartridge was curious if any gains in performance?
     

  2. Rocky Mountain

    Rocky Mountain Well-Known Member

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    Alot of people go the 7-300wsm way because it has a longer neck than the standard 7mm wsm which is a tad on the short side.
     

  3. J E Custom

    J E Custom Well-Known Member

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    Actually the 7 WSM has more case capacity than the 7-300 wsm and therefore is capable of
    more velocity with the same bullet with slower/more powder.

    It also has it's own Head space gauge, all other WSMs use the same head space gauge.

    The 7 WSM has a neck length of .244 and the 300 has a neck length of .298 for a difference
    of .054. With the case length the same for both (2.100) making the case body .054 longer
    on the 7 WSM.

    J E CUSTOM
     
  4. grit

    grit Well-Known Member

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    As stated, the 300 is actually smaller than the 7mm. There are two good reasons to utilize the 300 cartridge. First, Norma makes excellent brass for the 300. With the 7, you're stuck with mediocre brass and thorough brass prep. In my experience, this is a big factor. Second, the longer neck supports long bullets better and minimizes throat erosion.

    The 300 gives up nothing in performance. You get top quality brass and longer throat life. While the 7WSM is excellent, I prefer the 7-300.
     
  5. geargrinder

    geargrinder Well-Known Member

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    True, but it is a very simple fireform to make 7mmWSM from Norma 270 or 300wsm brass.

    The only real difference is the neck length.
     
  6. J E Custom

    J E Custom Well-Known Member

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    Good brass is allways a plus if you can get or afford it. I have never had a problem with the
    available brass even though I have had to discard a few in the initial case prep.

    I use to be a believer in the "At least one caliber of neck length philosophy" until a very learned
    gunsmith informed me that it was the amount of contact surface of the neck to bullet(Square
    inches) that made the most difference. the 300 Win Mag is a good example, inside Neck Diameter
    is .308 and inside neck length is .264 (.044 thousandths shorter) and the 300 WM is known for its
    accuracy.

    Lots of cases have necks shorter than the bullet diameter and accuracy is hot an issue. I still like
    the necks longer but do not fret over the ones that are not. So this would not be a reason for me
    to abandon or change to one that is not one caliber long.

    Why do we Improve cartriges ? Normally to get more case capacity to increase velocity.

    True there is little difference in the two but the advantage has to go to the 7 WSM in my opinion.

    Grit: I like and respect your post and opinions so in an effort to learn more I have a question.

    How can throat erosion be reduced by a longer neck ? The overall case length is the same and
    the bullet exits the brass at the same point and exposes the throat and chamber to gas and
    unburnt powder at the same time and place.

    This is not a smart ass question and I am always open to learn more.

    So the fact that the original poster ask the question "is there a substantial gain with a 7/300 WSM
    over the 7 WSM my opinion is NO, in fact like with any Wildcat there are other issues that you
    have to deal with.(Custom dies,brass with the wrong head stamp, lack of factory ammo ETC.

    The only reason I build wildcats for myself is to fill a niche that no factory round can or does.

    Again this is not to start anything just a question, and my opinion.

    J E CUSTOM
     
  7. grit

    grit Well-Known Member

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    To be completely frank, these sort of things are based on "likes and dislikes, theories and ideas". I'll argue a point while completely conceding to an opposing opinion. I've achieved excellent results with the 7WSM and the 7-300. I like the 7WSM a lot. I build a lot more 7WSM's.

    The Norma brass is better. I spend twice as long prepping Winchester brass, still toss a quarter of it, and still throw out every piece of brass associated with a flier. It bothers me, every time. I don't save any money with the cheaper brass. You could form 7WSM brass, but then you're giving up barrel life to fireform.

    The longer neck protects the throat a little because the confluence of the burning gasses is well inside the case. It's a theory I subscribe to, nothing more.

    I have ideas of what case design should be. The 7-300 is very good. The 7WSM has a short neck :D. Why have "close" when I can have "just right". I believe the extra effort pays off in tighter velocity spreads, fewer fliers....
     
  8. J E Custom

    J E Custom Well-Known Member

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