Optimum .300 wm Barrel Length

Discussion in 'Long Range Hunting & Shooting' started by 3fingervic, Jun 1, 2011.

  1. 3fingervic

    3fingervic Well-Known Member

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    I searched this site and googled it but couldn't find an answer. If I was building a .300 wm what barrel length would give me the best performance. Weight is not a concern, and it would be shooting 200+ gr. bullets.
     
  2. liltank

    liltank Well-Known Member

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    I was told by a Sniper trainer with decades of experience that a 26" barrel in a 1:10 twist is the optimal length needed for the the 300 Win Mag. If I were to build one, that is exactly what I would get. Get a taper of 1.200 to .875 with deep flutes.

    Tank
     

  3. 3fingervic

    3fingervic Well-Known Member

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    I have a .300 wm and the barrel still has a lot of life left. I was just thinking about a rebarrel in the future. I am finally getting the 208's loaded, and out of my 24" barrel it looks like I'm going to be around 2750 fps. I was thinking by adding inches to the barrel I could be closer to 3000fps? It's trivial I know, but just wondering
     
  4. trebark

    trebark Well-Known Member

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    by 'best performance' I assume you mean the barrel length that would produce the highest velocity. If that is true, I would think 28 or 30 inch would do the trick (leaning more towards 30).
     
  5. liltank

    liltank Well-Known Member

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    Your going to get more velocity with a longer barrel, but not necessarily what you are looking for. I've been struggling with this theory for the past couple years. Right now I have to bump my velocity up to 2950 for match my ballistics for my .308 that is chronoing at 2774 average. I'm thinking my chrony is a little off. I have to dial 14.25MOA for 645yds. Found that out today. That is why I missed a couple groundhogs several times today trying to hone in my dope. Finally put up the steel and got some hard data. So it is a matter of just trying to figure it all out.

    Tank
     
  6. 3fingervic

    3fingervic Well-Known Member

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    Tank,

    What velocity were you getting out of the WSM. You were shooting 208's, right. I'm not looking to sacrifice accuracy just to get 3000fps., and I wasn't looking to shoot a 40" barrel. I was just kind of trying to find out how long you would go and it still make sense.
     
  7. liltank

    liltank Well-Known Member

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    I was getting around 2850fps. There are guys able to push it to 2950, but for me that was killing my brass in 2 firings. 2750 to 2800 seemed to be a good speed for my 26" barrel. If you want 3000fps you might want to look at a 30+" barrel. Using H1000 or IMR7828 should result in the 3K you want.

    Tank
     
  8. Blackhawk41

    Blackhawk41 Member

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    Liltank is right on the money your gonna need a 30+ inch barrel. But that being said you need to look at practicality to of the weight and length of the gun. I've always been taught that the 308 to achieve full/maximum powder burn in theory needs a 36 inch barrel. So I'd bet you'd need close to that if not a few more inches.

    I'm sure somewhere there is a formula or formulas to calculate powder burn and expansion of gas in the barrel. But thats bound to change with heat, and powder types.
     
  9. joe0121

    joe0121 Well-Known Member

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    Those are some crazy long tubes. There is a law of diminishing returns. After 18 inches I would be shocked to see a .308 gain more than maybe 50 FPS per inch. I think a 1/10 twist at 26" is just the ticket( I hope so thats what my Krieger #10 mtu is) . Beyond that the results aren't really appreciable and the rifle soon become a bench queen.

    I mean look the the .338 edge guys drilling bears at 1200 yards and dropping them in their tracks. They are using .30 inch tubes.
     
  10. MSLRHunter

    MSLRHunter Well-Known Member

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    I have a 300wm with 26" bbl and my accuracy load with the 208gr Amax is at 2845fps. I have pushed the 208 to 2900-2925fps with retumbo, but accuracy suffered. If I were starting from scratch and building a 300wm, I would go with a 28"bbl that with a muzzlebrake would be right at 30" total length. With a 28"bbl you should be able to get to 2925-2950fps safely with the 208 and 210gr.
     
  11. 3fingervic

    3fingervic Well-Known Member

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    28" to 30" would be the general direction that I would go. Thanks for the great advise guys.
     
  12. lil 300

    lil 300 Active Member

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    Currently running a 28'' Rock Creek mtu contour. 72 grains of 4831 sc and 208 amax gets me 2955 2965 fps, that is my accuracy load. Gun weighs 17 and a bit, next barrel will be a 1.25 straight Rock at 29.25.