How close can flutes be to muzzle?

Discussion in 'Gunsmithing' started by sambo3006, Apr 26, 2015.

  1. sambo3006

    sambo3006 Well-Known Member

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    I've got a 6.5mm Benchmark fluted Remington varmint contour barrel blank (6 flutes) that will finish at 27". I really don't want it to finish that long. If it were cut to finish at 26" the flutes would end about 1" from the muzzle. Is there any minimum distance that the flutes can be from the muzzle for any reason other than cosmetics?
     
  2. J E Custom

    J E Custom Well-Known Member

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    For looks, 2'' to 3'' is best but 1'' would be just about my limit.

    If you install a brake after you cut it, it would look better because of the added length of the brake
    as long as you did not let the flutes get to close to the brake.

    If no brake is to be installed 1' to 1 1/2''would be good.

    Also, if it is still a blank you can take the same amount off the shank before chambering and it will look the best at a cut length of 26".

    J E CUSTOM
     
  3. jfseaman

    jfseaman Well-Known Member

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    Just for the sake of discussion.

    Other than looks:
    is there any reason a fluted barrel can't be cut shorter so that the muzzle is scalloped?

    is there any reason a fluted barrel can't be cut and threaded with the flutes terminating where the threads begin?

    engineering?
    safety?

    Of course it would be "ugly" but beauty is in the eye of the beholder.
     
  4. Edd

    Edd Well-Known Member

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    I would take JE's advice and cut a little off of the breech end. I think a barrel with that muzzle diameter will start looking odd with a smooth section shorter than about twice the diameter. Cutting just a small amount from the breech could leave you a 1.25" to 1.5" unfluted muzzle.
     
  5. Punisher

    Punisher Well-Known Member

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    You need to consider the diameter of the barrel at the muzzle. But for general work, you probably won't find a smith that will do less than 1" unthreaded or 1.5 with threads cut for a suppressor or brake.

    The closer the flutes come to the end, the more you open up to the possibility of a barrel failure. I have never seen it, or heard of it, but that's why nobody likes to go under around 1.5". Most flutes terminate 3" from the end of the blanks that I have seen.
     
  6. jfseaman

    jfseaman Well-Known Member

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    So you are saying there is an engineering/metallurgy reason to not cut shorter than the flutes so the muzzle is scalloped?
     
  7. Varmint Hunter

    Varmint Hunter Well-Known Member

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    I saw a shooter firing a rifle that was obviously shortened to the point that the fluting went to the muzzle. It looked odd but did not seem to present a problem. The rifle was chambered for a big bore cartridge but it didn't ask which.

    Presumably, the bore pressure would be at its lowest point at the muzzle so a structural insufficiency wouldn't seem likely to me. But then again, I just shoot rifles, I don't build them.
     
  8. IdahoCTD

    IdahoCTD Well-Known Member

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    I called Benchmark and asked Chris about shortening it into the flutes and he said it was fine, it would just look silly.
     
  9. sambo3006

    sambo3006 Well-Known Member

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    Perfect! Exactly the look I was looking for!:D

    The Remington varmint contour doesn't have a straight shank section so there is a limit to how far the breech end can be cut off. I'll probably Just have the muzzle end cut off 1" longer than the flutes and call it good. There is a method to my madness. I have a McMillan A5 edge stock it is going into and I don't want it to be muzzle heavy. Currently there is a 24" unfluted Rem varmint contour barrel in that stock and it balances nicely.
     
  10. IdahoCTD

    IdahoCTD Well-Known Member

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    That barrel is really light if I remember right, like 4lbs 1oz, at full length so I doubt it will be muzzle heavy compared to a 24" unfluted barrel. Most Sendero contours in 6.5mm run about 4 3/4lbs.
     
  11. J E Custom

    J E Custom Well-Known Member

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    Barrel failures normally only come one way, Catastrophic, there is no way to know when you are near failure or how close you came as long as it doesn't fail.

    Fluting a barrel all the way to the end creates stress riser's that could cause failures due to hoop
    strength loss. How much is two much ? it is anybody's guess, The non fluted barrel prevents a failure from starting (In Theory) at the end of the barrel Just like when you drill a hole at the end of a crack to prevent the crack from growing anymore.

    On the barrels I have seen that failed, (That were not overloaded)they all were small diameter and they failure started at the muzzle and followed the rifling (Fluting acts the same way only on the outside) Bullets that claim to have perfect expansion of the bullet nose, normally have strait groves inside to control the petal size and number by designing in these stress risers where they fail very evenly and informally.

    I would think that any non fluted portion on the end would be good to prevent failure.

    Also if you notice, no barrel maker flutes where the chamber is. Even though it is a much higher pressure area it is considered taboo .

    I don't think anyone can tell/predict how much is enough and probably wouldn't tell even if they knew so go with the barrel makers when you order a fluted barrel, they always ask, What is the finish length so head there advice.

    1" of barrel adds almost nothing to the weight so if its not a length issue I would leave it alone.

    Just My Opinion

    J E CUSTOM
     
  12. Punisher

    Punisher Well-Known Member

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    Yes. JE said exactly the same thing but was way more specific. Asking a smith to cut the barrel into the flutes is like kissing your sister... It's just not done.

    All you end up doing is engineering in the point of failure. It may not fail, then again, I sure wouldn't want to find out.

    JE is way more experienced than me, I just work on my own rifles. But the guy that taught me was pretty good. He is VERY precise and exacting. He taught me that safety is your priority, and don't make decisions that compromise that. A smith won't stay in business if his guns blow up.
     
  13. sambo3006

    sambo3006 Well-Known Member

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    I wasn't planning on having it cut off into the flutes. I was going to go with JE Custom's original advice and stay at least an inch longer. I think what I've decided to do is just finish it at 27". If I don't like it I can have it cut back an inch and recrowned later. That would still give me an inch to the muzzle of unfluted barrel. Thanks for all the input guys and thanks to idahoCTD for a smooth transaction on the barrel!
     
  14. Trickymissfit

    Trickymissfit Well-Known Member

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    taking a page from Bill Calfee's writings, Leave the last two or three inches untouched. Reason being is that when you remove metal at the muzzle, you release compressive stress and all the barrel to actually grow a few tenths. You always want the last three inches of the bore to be tighter than the other part. Bill ought to know as his rifles have won more bench rest shoots (most all rimfires) that anybody else.

    I'm in the camp that says to never touch the O.D. once the bore is cut.
    gary