I would like to find any information regarding barrel diameters and fluteing depth. Is there an industry standard for how thick the barrel wall should be from bore to bottom of the flute cut?
Im looking at fluteing a douglas #4 contour. Muzzel dia is .680 and bore is .358 (.358 norma magnum).

The sites i have checked regarding this are very general and dont give any answers that are usefull.

Welcome to the forum spiner. Rules are simple, be nice and join in.

Your best bet will be to talk to the folks doing the fluting, they will be able to tell you if that particular diameter barrel is doable. I don't know if there are any industry standards for fluting as it's a pretty simple milling operation. Perhaps some of our other members here can help you out. Brownell's and Midway both sell the fluting mills.

How deep you can go with fluting depends on outer barrel diameter, bore size and barrel metal. Some barrel makers feel it adds stress to the barrel and some will refuse to flute a stainless barrel in a larger caliber. Others claim fluting aids in cooling, and stiffness for barrel weight. I personally feel it neither helps nor hurts but it does look cool.

Fluting takes off weight, without reducing the stiffness of the barrel by as much as if you had taken off as much weight by reducing diameter. If that doesn't make sense, I'm sorry, but that is the correct explanation. Perhaps someone else can explain it better.

Anyway despite what you read in some of the gun rags, it never "adds" stiffness.

Any gunwriter who says it 'adds stiffness' just displays their ignorance of the topic, and frankly you should be real wary of anything else that person writes of a technical nature.

Differences in barrel cooling would be real, but probably marginal. Heat transfer between air and steel is poor to begin with, as air is actually a pretty good insulator compared to most materials. If you really want to aid cooling, a fan to speed up the airflow is the most effective way.

Hope that helps.

It isn't actually going to ADD stiffness to the barrel. However, the added stiffness relative to the weight of the barrel is real.

Or, other words, it's stiffer than an unfluted barrel of the same weight, but of smaller diameter.

It also increases the surface area of the barrel, and heat transfer becomes more efficient as the surface area increases. The price here is referred to as "specific heat". The more steel you have, the more efficiently it retains heat. And on and on.....

Hey thanks for the answers. I have a c/m barrel and are planning to do the fluteing myself as i have access to a mill, so will try and get some measeurements from a factory rifle or two and see what the wall thickness should be. The reason for this is for looks more than weight, I have a kimber varmit with s/s fluted barrel and the difference in cooling between that and my friends remmington v/s un-fluted I beleive is all in the imagination.
Im from New Zealand and things here are expensive, the cost of a gunsmith to cut 6 flutes is $250nz, around us$200 and the douglas barrel nz$675 about us$500.

Another question..what are the benefits of a removeable pilot chamber reamer compared to a solid pilot? Im just in the process of purchaseing one from PTG.

If you flute the barrel, realize you are inducing stress to the metal in doing so. The barrel should be reheat treated or cryogenic treated to relieve some of the stresses and realign the metallurgical properties.

The easist way to assist barrel cooling is relative easy and simple. Paint the barrel flat black!! Don't believe that? Look under the hood at your radiator--it's painted flat black. Next thing would be to add fins to the barrel which gives more surface area for air to metal contact. Flutting would be very crude fins so suspect the amount of additional cooling would be marginal if at all measurable.

Interest question posted as I had a discussion during a recent gun show with some gunsmiths over this same topic. The general concensus--it was stupid to do, derived very little if any benifits--but they would do it if it generated income for them. I believe the last part is the crux of the issue be it a manufacturer or gunsmith.

When making a barrel it is placed between centers and turned its entire length to get even wall thickness for maximum accuracy. This is after the solid blank has been bored, rifled and straightened. Now you're going to flute the barrel so lets assume a bull barrel for easy illustration. Its placed between centers and has to be aligned exactly dead center to the bore axis for the entire bore axis length. There are two ways of cutting the flutes--end mill or horizontal mill cutter. Either cutter is going to wear as its used thus the flutes will have a taper from one end to the other. Your going to cut how many flutes? Each will have a slight taper from the last one cut? Next you have to index each flute perfectly so many degrees, minutes and seconds otherwise one flute is spaced more that the one on either side. All this is ultimately going to affect accuracy.

The ultimate statement to me is it reduces weight!! Well it does remove some weight but you'd be better served to lose five pounds from your middle.