LRH Rifle - Barrel Contour

Discussion in 'Long Range Hunting & Shooting' started by Imho, Mar 29, 2011.

  1. Imho

    Imho Member

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    I'm torn between posting this here or in the Rifles, Bullets, Barrels and Ballistics forum, so hopefully I've picked the right place.

    Can someone help me with barrel contours, specifically what would be a good starting point for a LRH rifle buildup.

    Ideally I'm after a light-ish rifle but not a featherweight. I want to be able to walk around without thinking I have a HB varmint rig on my shoulder. The country I hunt varies from open grassy paddocks to forests with logged mountain sides. In both areas I'd be looking at shots in the 500 to 800 yard range, possibly up to 1000 yards at the extreme.

    The starting point is a Weatherby Vanguard SUB-MOA in .300 Win. Mag. After a bit of research it seems they have a #2 contour barrel from the factory. I measured the barrel as 0.615" at the muzzle. My first step will be to bed the action and free- float the existing barrel, but this can is bit of a crap shoot with a sporter weight barrel.

    The measurements I've seen for barrel contours don't seem to be consistent. The last one I saw had a #4 as being 0.650" at the muzzle and a #5 as 0.700", but that puts my standard barrel as close to a #3.

    So, I guess the question is what contour would be a good compromise between weight and accuracy when free-floated, and should I put up with the extra weight and go for a 26" barrel or stick with a 24"? I'm currently thinking 3/4 MOA for deer-sized game at the ranges I'm talking about.

    Thanks in advance.
     
  2. budlight

    budlight Well-Known Member

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    I'm jaded to 28 and 29 inch barrels for LRH. With twists for the heavy per caliber bullets. Logically you have think that just a few more inches is only a few ounces compared to the rest of the rifle.

    You go to any barrel man. and get the weight you want with the contour for the stock. The longer barrels allow you to load higher speed without stressing the cases. A long stick is so much easier to hold steady.
     
  3. Kevin Cram

    Kevin Cram <b>SPONSOR</b>

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    Each barrel mfg. has their own contour designations. From one to other they're close but not exactly the same. I install a lot of Brux barrels which uses Kreiger barrels contour page. I do several lighter long range rifles that are build off of a Brux #4 contour. It has a 1.250" breech diameter straight for 2.750" then Douglas taper to .900" 6" from the breech then straight taper down to .670" with a finished length of 26". It weighs in raw at 3 1/2 lbs. You can modify the contour to your specifications at no extra charge. A 24" - 26" is no huge deal. Most long range shooters are trying to get as much velocity and accuracy so they primarily use a longer barrel. A 24" in a 300 Win Mag would work just fine for shots out to 800 yards with the right bullet combination but 26" would give you a bit more edge, but not absolutely necessary. I would shoot for as small of a moa as you can and not settle with 3/4 moa. 3/4 moa is OK but 1/2 moa is better. Let me know if you need any help with your build.
     
  4. Imho

    Imho Member

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    Awesome. Thanks for the help guys. I think I'm on the right track with my thinking in terms of the contour range.

    I'll consider a custom contour too. The two I standard contours I was looking at were:

    #4 - 1.240" for 2.5" -> 0.840" at 7.5" -> 0.650" at 26" (no weight given for the #4); or
    #5 - 1.240" for 2.5" -> 0.900" at 7.5" -> 0.700" at 26" (4.5lb)

    Without the weight for the #4 it's a bit hard gauge if these barrels fall in a similar weight range to yours Kevin. Unfortunately the tyranny of distance would prevent me from having you do the work.

    I'm not really looking to save ounces. Hopefully the difference between the #4 and #5 in weight would be ounces, same as 24" versus 26". It all adds up I guess, and I would have to think about carrying more than 1-1.5 pounds more than my 24" standard barrel.
     
  5. WildRose

    WildRose Well-Known Member

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    I would doubt you are looking at more than an 8oz difference in weight between the two contours on the 24" bbl, and no more than a half ounce on the extra two inches.

    Depending on the load/powder the extra two inches can easily mean 50-100fps.
     
  6. Imho

    Imho Member

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    I got some more details and it looks like the difference between the #4 and #5 contours is only just over 5 1/4 oz (26").

    Based on that I'm leaning towards the #5 in 26". I think anything longer that that will start to get unwieldy for a walk-around rig.

    I'm still not certain though, the Brux #4 contour seems like a good compromise too.

    Decisions, decisions.

    Thanks again.
     
  7. WildRose

    WildRose Well-Known Member

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    The M-24 weighs in at around 15.0lbs, Same with the M-110 and we pack them all over places no hunter would ever want to go.

    I'd say you're making a wise choice.
     
    Last edited: Mar 30, 2011
  8. new shooter

    new shooter Well-Known Member

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    Kevin would a finish barrel at 26' say .750 flulted weight be about the same weight and would it be more accurate. Thanks for your input. Joe