Bolt flutes
Close
Login to Your Account
Page 1 of 2 12 LastLast
Results 1 to 20 of 26

Thread: Bolt flutes

  1. #1
    Join Date
    Feb 2007
    Location
    UK
    Posts
    73
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    0

    Post

    Could any one kindly explain the proses of helical fluting a bolt on a rifle. I guess you whuld use a mill and a bull head cuter but what methods are used a simple explination whould be great thanks.

  2. #2
    Join Date
    May 2005
    Location
    Interior British Columbia
    Posts
    2,268
    Post Thanks / Like
    Likes (Given)
    235
    Likes (Received)
    689

    Post

    You need a mill that will drive a universal indexing head for helical cutting, or a CNC mill with a 4th axis, and a controller that can handle the simultaneous moves.

    The universal indexing head has a gear train between the leadscrew of the table and the input shaft of the indexing head allowing a consistant ratio between the lead of the screw and the worm gear ratio, which allows rthe indexing head to turn a determined amount as the table moves a given distance, which gives you the helix.

    There is a bunch of math involved in calculating the gear trains, or you can look it up on the chart that should be with the head.

    Cheers
    Trevor Jones

  3. Likes Butch Lambert liked this post
  4. #3
    Join Date
    Nov 2006
    Location
    littlestown,pa
    Posts
    1,763
    Post Thanks / Like
    Likes (Given)
    72
    Likes (Received)
    20

    Post

    But whats the reason for them?

  5. #4
    Join Date
    Apr 2005
    Location
    Vallejo,Ca USA
    Posts
    207
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    2

    Post

    Looks cool,no other reason.

  6. Likes Butch Lambert liked this post
  7. #5
    Join Date
    Sep 2004
    Location
    North Olmsted, Ohio
    Posts
    91
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    12

    Post

    Lumpsmith

    The benchrest guys do it to reduce weight so a heavier stiffer barrel can be used.

  8. #6
    Join Date
    Apr 2007
    Location
    N. MN
    Posts
    153
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    0

    Post

    I think Walker nailed it. I have a gun that I picked up at a gunshow where the folks that built it didn't have the technology to do the spiral fluting. The bolt (XP-100 action) was reduced in diameter (between the lugs and bolt-handle) and the dog-leg was drilled full of holes to get the gun under the legal limit. It also have a very short, heavy barrel.

  9. #7
    Join Date
    Jan 2007
    Location
    Sierra Nevada Mountains - Motherlode, CA USA
    Posts
    552
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    12

    Post

    I believe they are for either esthetics or weight loss (minor). My Remington 700 Titanium has spiral fluted bolt, seems only to reduce more weight.
    I was just thinking out of the box and I could easily cut spiral flutes on a bolt with my Monoset.

  10. #8
    Join Date
    Apr 2005
    Location
    Vallejo,Ca USA
    Posts
    207
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    2

    Post

    To make them "lighter" you got to be kidding. How much weight do you think is in those little cuts? Now the ones on the bbls might reduce the weight a noticable amount also the ones on the bbl help to cool the bbl,more surface area.

  11. #9
    Join Date
    Feb 2007
    Location
    UK
    Posts
    73
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    0

    Post

    Thanks, i think they are just for show and are personal taste. i was interested to know how they were cut though.

  12. #10
    Join Date
    Jul 2003
    Location
    VA
    Posts
    301
    Post Thanks / Like
    Likes (Given)
    1
    Likes (Received)
    10

    Post

    A fluted bolt does reduce weight some. There are other places where you ca shed some ounces.

    It also helps in making the bolt smoother to the feel of operation. Less surface area means less drag or friction. The diameter stays the same, but much less drag.

    The spiral is just one way of doing it, there are straight flutes, and even diamond pattern flutes. All serve the same purpose.

  13. #11
    Join Date
    Dec 2005
    Location
    Kalispell, Montana
    Posts
    1,256
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    12

    Post

    Lumpsmith,
    BR guns have to weight a certain amount for a given class, the less weight you pack else where means the more you can put in the barrel. Yes, trivial amounts but it can and does make a difference
    Jim

  14. #12
    Join Date
    Feb 2007
    Location
    UK
    Posts
    73
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    0

    Post

    I think it has to be more for fancy than any other thing.
    The angled flutes and the bolt drag point?
    ... Whould you not think that straight flutes whould be more practical at smothing bolt operation? Or am i mising some thing.

  15. #13
    Join Date
    Apr 2005
    Location
    Vallejo,Ca USA
    Posts
    207
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    2

    Post

    I realize that there are weight limits for the different classes,and I am not trying to be a "richard head" but you are'nt going to save enough weight to make it worth the time and money. the only thing that is lighter is your wallet.
    Do you remember the big to do in the hot rod world when Isky cams came out with their 5 cycle cams? It was going to revolutionize the hot rod/racing world never happened because it was all hype. In my opinion this is the same thing.

  16. #14
    Join Date
    Oct 2002
    Location
    Poetry Texas USA
    Posts
    1,776
    Post Thanks / Like
    Likes (Given)
    321
    Likes (Received)
    222

    Post

    My BR bolts are helical fluted in a diamond pattern. Yes it saves a little weight, but more importantly it is smoother as our bolts are a very close tolerance fit unlike a production bolt. Gives a little space for trash to fall into. My BR bolts have only .001 total clearence. No room for a little trash.
    Butch
    www.shadetreeea.com

  17. #15
    Join Date
    Sep 2006
    Location
    Texas
    Posts
    32
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    4

    Post

    If you use straight flutes on a bolt, it is possible in certain rifles/calibers that the top cartridge in the magazine will rise up into one of the flutes when rotating the bolt. Not good.

    If you use helical flutes this problem is avoided.

    Yes you are removing only a very small amount of weight but there is a saying,"watch the ounces and the pounds will take care of them selves".

  18. #16
    Join Date
    Apr 2019
    Country
    UNITED STATES
    State/Province
    South Carolina
    Posts
    2
    Post Thanks / Like
    Likes (Given)
    4
    Likes (Received)
    0

    Default

    Fluting a rifle's bolt theoretically gives debris and dust a place to sit without compromising the rifle's functionality. However, unless you're fighting in the trenches of Passchendaele, or Operation Torch in the Sahara of Africa, Your rifle's fluted bolt isn't going to give you any actual advantage in real life.

    Some might disagree with me, citing that fluting the bolt contributes to weight reduction; to that, I concede. However, a fluted bolt reduces the rifle's weight to such an insignificant degree that, unless you're focused on making the lightest rifle physically possible and have an excess of money at your disposal, you are better off just buying a normal bolt or just using the factory bolt.

  19. #17
    Join Date
    Nov 2006
    Location
    Greenwood, Ca
    Posts
    947
    Post Thanks / Like
    Likes (Given)
    47
    Likes (Received)
    308

    Default

    Quote Originally Posted by jabezkin View Post
    But whats the reason for them?
    To make your wallet lighter.

  20. Likes Butch Lambert liked this post
  21. #18
    Join Date
    Nov 2006
    Location
    Greenwood, Ca
    Posts
    947
    Post Thanks / Like
    Likes (Given)
    47
    Likes (Received)
    308

    Default

    I’d argue that fluting the bolt body of a 2 lug bolt in the ejection port area has zero benefit, and probably had more potential for lockup from debris than a smooth bolt body.

    As far as weight savings on BR rifles, there’s probably more weight in fancy stock paint than was saved by fluting the bolt...

    My personal rifles have smooth bolts. My available for purchase rifles/barreled actions have fluted bolts. I don’t believe in them, but I have to sell what people want/think they need.

  22. #19
    Join Date
    Oct 2002
    Location
    Poetry Texas USA
    Posts
    1,776
    Post Thanks / Like
    Likes (Given)
    321
    Likes (Received)
    222

    Default

    Quote Originally Posted by 300sniper View Post
    I’d argue that fluting the bolt body of a 2 lug bolt in the ejection port area has zero benefit, and probably had more potential for lockup from debris than a smooth bolt body.

    As far as weight savings on BR rifles, there’s probably more weight in fancy stock paint than was saved by fluting the bolt...

    My personal rifles have smooth bolts. My available for purchase rifles/barreled actions have fluted bolts. I don’t believe in them, but I have to sell what people want/think they need.

    You sell the sizzle, not the steak!

  23. #20
    Join Date
    Dec 2017
    Country
    UNITED STATES
    State/Province
    Idaho
    Posts
    369
    Post Thanks / Like
    Likes (Given)
    104
    Likes (Received)
    84

    Default

    I weighed a couple long action Rem 700 bolts and it saves maybe an ounce with spiral flutes. They shoot better though 😀


Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •