Fluting

Fluted Barrels

Fluting barrels for both competitive target and hunting rifles is quite popular. There are two advantages to using a fluted barrel. Improved accuracy is one advantage because of increased barrel stiffness. If we compare a fluted barrel to one that is not fluted, both weighing the same, the fluted barrel is stiffer. This is because the fluted barrel will be of a larger diameter than the un-fluted barrel of the same weight and length. Increasing the diameter of a barrel greatly increases its rigidity. Fluting may also allow for a longer barrel, if weight is a consideration. Another advantage to fluting is the increased cooling rate of the barrel because of the greater amount of surface area exposed to the air. Please look at our FAQ section on fluting too. As of April 2015 we are also now offering spiral fluting. To see more information about spiral flutes – Click Here

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CNC 4-axis milling machine used to flute barrels.

We machine 6 flutes that are .219″ wide into the barrel. The amount of weight removed by fluting depends on the length of the barrel and the flute depth. The depth of the flute is determined by the contour of the barrel and the caliber. Flute length depends on finished barrel length. Normally the flutes stop 1.50″ short of the muzzle. When ordering a fluted barrel, please specify the finished length of the barrel so we can machine the flutes to the correct length. Fifty caliber barrels are fluted using a .312″ width cutter.

If you have a question about weight removal from fluting, we can help, but here are a few examples: A fluted .243″ caliber barrel of NBRSA HV taper and 24″ long weighs approximately 5 Ibs. – 6 oz. A fluted #6 contour barrel in .308″ caliber and 24″ long will weigh approximately 3 Ibs. – 14 oz. A fluted #5 contour .284″ caliber barrel 24″ long will weigh approximately 3 Ibs. – 5 oz. Fitting and chambering a barrel will remove approximately 3 oz. We only flute stainless steel barrels, the exception being chrome-moly steel fifty caliber barrels. Barrels suitable for fluting include any of the straight taper benchrest contours, straight cylinder barrels, #4 contour sporter barrels (or larger) up to 30 caliber and #5 or #6 contour barrels (depending on caliber) over 30 caliber or any of our three standard fifty caliber contours. The maximum length barrel that can be fluted is 36″. We can also flute 15″ long XP 100 type barrels of suitable diameter. You may also be interested in downloading a free copy of an Excel file we have available that will compute the weight removed by fluting. Click Here.

All of our barrels are furnished with a 320-grit centerless-ground finish (the exception to this finish is our octagon barrels) on the exterior and are sealed in a 6-Mill poly tube.

FlutingFluting1

 

Spiral Fluting

We are offering spiral fluting now in a number of configurations. We have a macro CNC milling program so the number of flutes, twist rate of the flutes and finish length are easily entered into the program.

The milling cutter is a .250″ ball end mill.  The maximum number of flutes is 9 depending on the contour size.  Five or six flutes would be the most common.  We enter the depth depending on the contour size and caliber.  Flutes are stopped 1.5″ short of the customer’s specified finish length.

spiral_flte_samples

(Click on the image for a larger view)

From left to right :

4 flute 3.5” twist 23” finish

4 flute 4 “ twist 28” finish (shop note: 7 flute, stop cutter after 4th flute)

7 flutes 12” twist 28” finish

6 flute 26” twist 26” finish

9 flute 9 twist 25” finish

5 flute 12 twist 27” finish

 

 

From left to right:

4 Flute 4 Twist

5 Flute 7 Twist

6 Flute 6 Twist

8 Flute 23 Twist

7 Flute 18 Twist

8 Flute 15 Twist

 

We are now offering Diamond fluting as of June 2017. Price for Diamond fluting is $190. The same .250″ ball end mill is used. Depth is determined by the contour size and caliber. The first picture is the standard flutes and twists. For the flutes to start and stop on top of each other, the finish length has to be a whole number. For example, if you where to order a 4 Flute, 4 Twist, with a 26″ finish length, the diamond pattern would match up perfectly. But, if you where to order that same flute and twist, but with a 26 1/2″ finish length, the flutes would look like the third picture.

 

 

 

 

 

 

 

 

From left to Right:

3 Flute / 3 Twist

4 Flute / 4 Twist

5 Flute / 5 Twist

6 Flute / 6 Twist

You can order any flute and twist that you would want, but the flutes might not line up. For example, the second barrel from the right, 6 Flute 25 twist. Also see last picture.

From Left to Right

4 Flute / 8 Twist

6 Flute / 8 Twist

6 Flute / 12 Twist

6 Flute / 25 Twist

3 Flute / 12 Twist