Barrel Fluting Question

[benchracer]

It seems like some barrel manufacturers are somewhat quirky about barrel fluting. Some won't do it at all. Others will only flute certain contours. I have thought about ordering the barrel I want and just having a gunsmith do the fluting work. Here are my questions:

1. Can fluting harm the accuracy potential of a given barrel blank?

2. Does it matter when in the production cycle the fluting is cut?

3. If a barrel is fluted post-production, are there additional operations that are advisable (stress relieving or cryo treatment, for example)?

I am asking this because I recently acquired a sporter weight .300WM with a VERY thin barrel contour. It feels so nice to carry, but the barrel heat walks severely after the second shot (and it is generously free-floated), feels like you could cook an egg on it after the third shot, and the rifle is light enough that it smacks me around pretty good.

I would like to go with a barrel just heavy enough to mitigate recoil a bit and remain stable through a single 3 shot string. I am thinking a fluted #4 profile barrel would do the trick, but such an animal is not offered in the make of barrel that I want. If it is a practical idea to order the barrel and have a gunsmith do the fluting work, I would like to go that route. I just want to be aware of any pitfalls inherent in doing so.

 

[J E Custom]

It seems like some barrel manufacturers are somewhat quirky about barrel fluting. Some won't do it at all. Others will only flute certain contours. I have thought about ordering the barrel I want and just having a gunsmith do the fluting work. Here are my questions:

1. Can fluting harm the accuracy potential of a given barrel blank?

2. Does it matter when in the production cycle the fluting is cut?

3. If a barrel is fluted post-production, are there additional operations that are advisable (stress relieving or cryo treatment, for example)?

I am asking this because I recently acquired a sporter weight .300WM with a VERY thin barrel contour. It feels so nice to carry, but the barrel heat walks severely after the second shot (and it is generously free-floated), feels like you could cook an egg on it after the third shot, and the rifle is light enough that it smacks me around pretty good.

I would like to go with a barrel just heavy enough to mitigate recoil a bit and remain stable through a single 3 shot string. I am thinking a fluted #4 profile barrel would do the trick, but such an animal is not offered in the make of barrel that I want. If it is a practical idea to order the barrel and have a gunsmith do the fluting work, I would like to go that route. I just want to be aware of any pitfalls inherent in doing so.

I will try to answer your questions based on my experiences.

#1 = It most definitely can, if not done right or at the right time while in production.

#2 = Fluting definitely should be done during production of the barrel if at all possible
because of the risk of screwing the barrel up. For years, I would not flute any barrel
because of the problems that I had experienced personally. If a barrel maker doesn't flute his
barrels you should not flute it later because his process is not built around fluting and
can/could cause accuracy problems.

#3 = Barrels come ready to shoot and any additional procedures could/may cause problems.
Most barrel makers will void there warranty because they don't have control of the process
and the craftsmanship.

I have first hand experience with fluting after the barrel was shipped and none have been good
so now if I want a fluted barrel ,I have the barrel maker do it as part of his process and guaranty
his work and quality of the barrel.

The reason "All" barrel makers have a minimum contour that they will flute is SAFETY. Barrel wall thickness is very important and If this is not held to a minimum The barrel can fail. (I am sure you have seen pictures of barrels that have split at the muzzle and if you noticed they are all very small contours and split in the rifling. Fluting will produce the same results if not done properly.

When Installing a muzzle brake the minimum wall thickness of the muzzle after threading is .200
for the same reason "SAFETY".

A good smith will not exceed this thickness minimum to flute your barrel ether so when you are told not to flute by the barrel makers and the smiths, Take there advice.

Light weight barrels are notorious for the problems you are having with heat but most of the time they are intended for carry, and only one or two shots max.

A good way to save weight is to shorten a heaver contour and go to a composite stock. light contours
have no advantage in accuracy just weight.

There is something that can sometimes help a light barrel. thread a weight on the barrel or a muzzle brake. The extra weight will often times help reduce the barrel harmonics and improve accuracy.

Just my opinion.

J E CUSTOM

 

[benchracer]

Thank you for such in-depth answers to my questions, all of which make perfect sense.

I like a good light contour barrel in the right chambering. My .300WM just breathes too much fire for such a light barrel to work very well. I want to fix its deficiencies without turning it into a Sendero. I was planning to keep barrel length at 24". Since fluting isn't likely to get me where I want to go, I will just have to choose the barrel contour with great care.

Thanks, again, for your advice.

 

[Derek M.]

I've HEARD that in general terms, it is BETTER to flute a cut-rifled barrel than a button rifled barrel due to the machining process. Cut barrels continue to do just that, cut away. Button barrels displace metal and get stress relieved.

Hart fluted my barrel during their process but I have not shot it yet. It's a 338 Edge. The only other fluted barrel I have is a PacNor on my 30.06. John Noveske did that one AFTER my rifle was built by him. He called me up one day about a year or 2 after I had been hunting with it and told me he got a fluting tool and wanted to offer fluting my bolt and barrel at no charge so I took him up on the offer.

He spiral fluted my bolt and reblued it and straight fluted my PacNor barel. He assured me I would not be able to tell any difference in my existing loads. He was correct for what it is worth.

 

[Edd]

You are never going to get a consensus on barrel fluting. I know of one Gunsmith that cuts the flutes on a finished barrel with a single pass and no coolant. It seems like his guns shoot as well as anyones.

 

[BountyHunter]

Cut rifled barrels can be fluted after with no effects.

Button rifled barrels fluted later will change internal dimensions. Will it effect accuracy? Maybe, so why do it.

Tim North (Broughton Barrels) fluted one my barrels for a comp gun due to weight issues after it was chambered. He kept track of the internal changes and had to relap and stress relieve it again to keep it in uniform specs. Most of your local gunsmiths cannot do that and do not have any way to even measure the changes. Sometimes you might get lucky and sometimes not, but there is a reason they tell you not to flute a button rifled barrel after mftr.

 

[Edd]

That is an example of what I was talking about. I've read comments by JE Custom stating why you will have more issues with a cut rifled barrel than a button rifled one.

 

[etisll40]

That Tim North is good, I have 1 of his barrels. Awesome shooter in 7 stw.

 

[Derek M.]

Of course I'm not a barrel maker, but wouldn't it make sense to drill the hole through the steel, then contour the barrel as desired, then flute it, then rifle it and then lap it? i.e., make all the cuts first before starting on the important stuff down the bore.

 

[J E Custom]

There is some question about the difference between buttoned and cut rifling barrels being fluted.

The difference is in the manufactures process. A premium buttoned barrel is stressed relieved/Heat treated twice because of the process. Once by the mill that allows the barrel maker to drill,ream and rifle without to much dimensional movement in the barrel blank. after contouring and/or fluting the barrel has to go back and be heat treated again because of the stresses applied during the process.

Some of the buttoned rifles are not heat treated the second time and these should not be fluted
later.

Cut rifled barrels come from the mill heat treated just like the buttoned rifle barrel but do not require the second heat treat and there for can be fluted later with little or no chance of a problems
The exception being if the fluting is poorly done it can change dimensionally and hurt accuracy.

The reason I recommend that the barrel maker do the fluting is that the fluting proceeds the last heat treatment and then the barrel maker does his final dimensional checks that assures it is within his tolerances.

Cut rifled barrels are dimensionally checked and approved without the second heat treatment and as long as the fluting is done correctly the risk of effecting the dimensions are minimum.

There are many reasons I like the buttoned rifled barrels better than the cut rifled barrels and there are others that feel the same way about cut rifled barrels. I personally have had great luck with both type of barrels made by some of the premium barrel makers but have not had the same luck with fluted barrels from some manufactures that were done later.

So whether you like the buttoned rifling or the cut rifling get the barrel maker to flute it and then he has total control of the process and total responsibility for the quality.

There are some smiths that can do an excellent job of fluting, as long as they get an excellent barrel that has been properly manufactured and heat treated. But the best smiths cant make a silk purse out of a sows ear.

The main point I am trying to make is Fluting, even if it is done right does not guarantee that it will be a shooter. There may be some but, I have never seen a bench rest barrel that was fluted, And I assume that it is because there is to much of a risk of inaccuracy so it is not done.

We all know how good it looks but they must not think they look good or there is another reason.

Just my opinion based on my experiences, and knowledge of heat treating and the barrel making process.

J E CUSTOM