Barrel Fluting

Hi guys,

can anyone tell me how many of the top 50 benchrest or other high-accuracy competition shooters out there are using fluted barrels? And why?

I'm talking in the last few years, like at the most recent super shoots, rather than 15 years or so ago or whenever someone first started the fluting fad.

From what i can determine there are pros and cons with fluting, with the cons far outwaying the 'claimed' advantages. Constructive comments only please - with claims that you can back up, rather than tyre-kick chatter.

Flame suit on - fire away !!!

Thanks,

Dean.

Maybe a tire kicker

The main attraction to the competitive bench rest guys is the weight savings.

Bench rest shooters like trap shooters are all nuts so I don't like to ask them to much. But every one I've questioned wants velocity without sacrificing rigidity and adding weight. Which adds up to more barrel but less barrel. Personally I don't care for flutes but I don't like brakes either. But I still have to pay my rent and other bills so I LOVE flutes and I LOVE brakes. Oddly enough, the better shooters do seam to be still winning with fluted barrels so the bad press they have been given may just be ever so much BS, like a lot of other things in this industry. Or they may be shooting good enough to overcome the handicap. Time will tell I guess.

I got a brain storm and ran a test piece the other day on a piece of 1 inch aluminum while I had the machine set up just to see what it would look like with 6 full flutes and 6 half flutes using a 1/8th 2.5 inch key way cutter rather than a 1/4 or 3/32nd sprocket cutter. Its different I guess. So far no takers on the idea but it does look sort of cool. If you like splines on guns.

Dean most internet discussions are tyre kicker chatter.
If you want an informed answer ask the Aussie Benchrest shooters as most of them use a fluted barrel in their Sporter class, with a weight limit of 9lb it's almost the only way to meet the weight limit.
As for the Supershoot, I honestly can't recall anyone using fluted barrels although I think one really good shooter just about always used a fluted barrel and still managed to win.

Try asking the question on Benchrest Central.

Cheers
Kiwi

Most Benchrest shooter flute only for weight reduction as already stated and most don't flute because they run through a lot of barrels and it adds considerable expense to the barrel chambering. Personally I don't think it adds to or detracts from accuracy it just allows a heavier barrel contour with the same weight.

Gary

I have built quite a number of hunting rifles, and fluted approx 50% of them. All of them shot sub moa groups with my handloads. Hunters like the reduced weight of the fluted ones.. I use either 7 or 9 flutes, only because my mechanical engineer nephew says they are stiffer than even number flutes, There, that last sentence should stir things up.

I can't really say that I have ever heard of uneven fluted barrels being stiffer than an even number of flutes. Nor have I ever seen an uneven number of flutes on a barrel. Well, that I have took notice of anyway. It must be a slight improvement if any, or everyone and their dog would be doing it. It has been my observation though, that a solid team of engineers can turn a $100 project into a $100 million boondoggle if you keep paying their salaries long enough. I don't use fluted barrels on my own guns because I simply don't like the look. If I want a barrel lighter I just order a lighter conture or turn it down. One would think a gun plumber would have enough before and afters from customers that he should have a better idea but such is not the case. Once the customer has the gun back you generally don't see or hear from them for months and often years and most jobs I do are forgotten a week after they are completed. More times than I can remember a guy will come in and say I want you to do this and I will reply with, "I dunno, I don't think I have ever tried that." Then they give me the bovine stare and say, "well you did one for me just last year." At 90 or so guns a month things get a bit blurry and after 31 years nothing much is new so I think I try to block most stuff out. I have to think that a lot of the bad press fluting gets is just BS. To many people, in to many bars, bad mouthing things they know nothing about, have no experience with or are to cheep to get done to their own guns. If it was indeed problematic, people wouldn't be getting it done and manufacturers the likes of Weatherby, Remington and Sako just to name a few wouldn't be using it. Like smokeless powder I think it's been around long enough to be more than just a fad now. Even if I don't like it.

I Don't much like it ether but when a customer wants it done, it gets done, and I make a bit of $. everyone is happy!

glbreil said:

Most Benchrest shooter flute only for weight reduction as already stated and most don't flute because they run through a lot of barrels and it adds considerable expense to the barrel chambering. Personally I don't think it adds to or detracts from accuracy it just allows a heavier barrel contour with the same weight.

Gary

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This is correct. At the IBS Nationals this year, and about 3 before that, I could count the number of fluted barrels on one hand and have fingers to spare. Benchrest guys use barrels of the right contour and know where to cut it for the right weight. They know exactly what the barrel must weigh to stay in the weight requirements.

speerchucker30x3 said:

I can't really say that I have ever heard of uneven fluted barrels being stiffer than an even number of flutes. Nor have I ever seen an uneven number of flutes on a barrel. Well, that I have took notice of anyway. It must be a slight improvement if any, or everyone and their dog would be doing it. It has been my observation though, that a solid team of engineers can turn a $100 project into a $100 million boondoggle if you keep paying their salaries long enough. I don't use fluted barrels on my own guns because I simply don't like the look. If I want a barrel lighter I just order a lighter conture or turn it down. One would think a gun plumber would have enough before and afters from customers that he should have a better idea but such is not the case. Once the customer has the gun back you generally don't see or hear from them for months and often years and most jobs I do are forgotten a week after they are completed. More times than I can remember a guy will come in and say I want you to do this and I will reply with, "I dunno, I don't think I have ever tried that." Then they give me the bovine stare and say, "well you did one for me just last year." At 90 or so guns a month things get a bit blurry and after 31 years nothing much is new so I think I try to block most stuff out. I have to think that a lot of the bad press fluting gets is just BS. To many people, in to many bars, bad mouthing things they know nothing about, have no experience with or are to cheep to get done to their own guns. If it was indeed problematic, people wouldn't be getting it done and manufacturers the likes of Weatherby, Remington and Sako just to name a few wouldn't be using it. Like smokeless powder I think it's been around long enough to be more than just a fad now. Even if I don't like it.

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Yeah, but you don't always here about the ones that go bad. Fluting proponents may want to check this out. The manufacturer refused to warranty it. Guy suffered some hearing damage, as well as ruined pants.....

Ah yes the old banana split from a plugged bore. Flutes are always cut to a depth of what is considered to be minimum safe bore diameters. It basically amounts to the diameter of a number 1 Shilen or Douglass conture. Basically speaking if one were to grind or turn the flutes off you would have what is considered to be a minimum safe conture remaining. Barrels do not split just because they were cut to minimum diameter, or fluted to minimum diameter. Nor does fluting make the barrel weaker. It is still just as strong as a minimum conture barrel. There has to be a reason for the barrel to split. There could of course be a fault in the steel from the rolling process like Remington had many years back with the 17 caliber barrels or it could be that the steel was burned in heat treatment and crystallized. In those cases the manufacturer would always just knuckle under and pay the guy out and then go after the barrel maker. In the photos above what I see is an obstruction related bulge that caused the barrel to split. I see a half dozen just like it per year. The telling evidence would be on close examination, a bulge was probably revealed. A bulge means the gun was fired with an obstruction in the bore and I'm sure that none of us would warranty anything caused by customer oriented idiocy. If the guy had a legitimate case he would have contacted a lawyer and a metallurgist and he would have had a case and sued and won. Obviously no one wants anything to do with him so obviously he has screwed up and won't admit it and now he is crying foul. This is one of the reasons that insurance for gunsmiths in North America costs $10,000 a year.

ADD NOTE: After looking at the photo again I would be willing to bet a box of beer, that if we were given a chance to look at the barrel, up close, we would find that the bulge is located almost exactly 1 inch down from the muzzle and that the split began on the UNFLUTED portion of the barrel, and continued downward into the fluted area. And I'm no gambler. I only bet when I'm sure I'm going to win.

The best way to get a fluted barrel, if you want to ensure the barrel is as it should be, is the have the maker flute it after it is contoured, then lapped after all is done. This way, the bore is consistent all the way through. And it is guaranteed.

rws is correct. Fluting is 99% for somebody that thinks it is cute only. BR shooters buy the correct contour barrel. Skip Otto,deceased, is the only BR shooter that I know that shot fluted barrels all the time. Skip made a lot of money fluting barrels. He had a very large horizontal mill and would flute 3-4 BR barrels on one setup at one time. He did hold the NBRSA 200yard 5 shot group at 200 yards until the last year or 2. His group size was .098".

Splines belong on drive shafts. Unless I'm paid to think otherwise.

"Barrels do not split just because they were cut to minimum diameter, or fluted to minimum diameter. Nor does fluting make the barrel weaker. It is still just as strong as a minimum conture barrel."

The fluted barrel to minimum diameter is not as structurally capable to internal pressure as a barrel turned to minimum diameter. It may not seem so since there's plenty of steel there but stress concentrations occur when material under stress (here hoop and axial stresses) has abrupt changes in section such as flutes create.

It might seen anti-intuitive but it's fact.

DaveE907 said:

"Barrels do not split just because they were cut to minimum diameter, or fluted to minimum diameter. Nor does fluting make the barrel weaker. It is still just as strong as a minimum conture barrel."

The fluted barrel to minimum diameter is not as structurally capable to internal pressure as a barrel turned to minimum diameter. It may not seem so since there's plenty of steel there but stress concentrations occur when material under stress (here hoop and axial stresses) has abrupt changes in section such as flutes create.

It might seen anti-intuitive but it's fact.

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Speerchucker, you are half-right so maybe that entitles you half a box of beer! These photos were from about 8 years ago when a customer brought this one in for 'repair'. Inspection did reveal a slight swell/bulge in the barrel about 1/2" back from the crown. The customer swore on oath that there was nothing in the bore that he knew of, so i could only determine that it was a bit of dirt in the muzzle if he had a bit of a fall while out hunting. (unless he was flat out lying about it....). HOWEVER, close inspection revealed that the rupture point actually started about 1 1/2" or so further back at the flutes, and it all unravelled from there.

I was going to explain about the fluting causing stress concentrations at the weak point (the flute cut) but DaveE907 has already hit the nail on the head, and he is correct. In a skinny round barrel the whole barrel wall will 'swell' in uniform manner, but on a fluted barrel the thick sections will not expand as readily as the thin sections - and if the pressure is high enough and you reach or exceed the proof stress yield point at the thin web areas then, well, you can see the results for yourself.....

I have found that in similar circumstances a non-fluted barrel will just swell a bit and the obstruction (usually dirt or snow, or oil ) will pass. Shorten the barrel back behind the bulge and re-crown and the customer still has a useable rifle.

I know alot of guys rag on a about Sako-type extractors being 'potentially dangerous' (in an over-pressure situation), but how many guys would consider their fluted sporter barrel to be 'potentially dangerous' as well?

While there are changes in the load bearing areas of fluted barrels these changes don't begin to become a factor until the safe working pressures of the firearm have been far exceeded to the point where metal has began to move in a permanent fashion. All Sako rifles are proof tested to C.I.P. standards before leaving the plant. They are not provisionally proved like many other firearms today where the design is proved and left at that. Each gun is proof tested. I know this for a fact because I approached a couple Sako/Tikka representatives years ago when I was doing proof work for Remington. Arguing that fluted barrels are unsafe is much like arguing if Sako extractors are unsafe. Its a pointless argument. They are perfectly safe until you do something stupid with them which they were not designed to do. People often try to start these arguments with me at work and I just tell them to get into their car and get it up to 100 miles an hour and crash it into a brick wall or bridge abutment. It has an airbag so they can't get hurt. Then they quickly try to argue that air bags are not designed for that. Well, its the same thing. Taking barrel pressures to where its expanding to the point that the metal is actually beginning to move and stretch is a pointless exercise and a mute argument. It has suffered permanent damage either way. The relative level of damage is irrelevant also. You were not supposed to subject it to that in the first place. Most of these arguments begin because someone has done something stupid, weather by accident or on purpose thinking that they could get away with it and realizing after the fact that it may not have been such a good idea. It seams to be human nature to try to place the blame on some one else and in the mean time try to make someone else pay for their stupidity. I have been forced to deal with a lot of these people over the years while doing warranty work for the manufacturers. Now days I have nothing to do with warranty work. I no longer need it or want it and when I get one of these "I've been wronged and I'm so hard done by" people in the shop, I'm quick to spin them around and hustle them out the door with a don't come back sticker on their back and a big L pasted on their foreheads. I've found most all of them are losers and thieves and are potentially, very expensive to have around. Lets face it if they want you to help them squeeze money out of someone else its just a matter of time before they are trying to steal it from you. You can bath a pole cat but hes just gonna stink again tomorrow.

ADD NOTE: Of course I have only seen about dozen split, fluted barrels in person. But only because fluted barrels are new comers to the game. I can't begin to recall how many unfluted split barrels I have seen. I have noticed that when the fluted barrels are bulged in the fluted area the split will run along the flutes until it reaches the chamber area and the muzzle area and then the split stops abruptly giving them an old fashioned, hand crank, egg beater look. Also when the split reaches the unfluted portion of the muzzle, half of the split will often separate leaving the unfluted portion of the muzzle attached to one side of the split. I would be willing to double down on that box of beer and re-bet that it actually did start to split in the muzzle area where the bulge occurred and then moved into the fluted area. Otherwise the muzzle area would have remained unsplit. I have also reclaimed two fluted barrels that were only bulged. One had to be cut and crowned in the fluted area the other in the unfluted muzzle area.

Oddly enough I have NEVER seen a split follow the grooves in the rifling in ANY rifle barrel. Even ultra thin pencil barrels. It always follows the grain structure of the steel right across the lands and grooves. This leads me to wonder if a split would follow the flute in a spiral fluted barrel or would it follow the grain structure in the steel and split through the lands of the spiral flutes like it does through the rifling? If it did indeed follow the grain line it would more or less show that the theoretical loss of strength from fluting is more hypothetical than practical. Just like it is with the loss of theoretical structural strength from rifling barrels. Most of us know from observation that forces from over taxation from pressure will almost always ignore certain physical dimensions and irregularities in the vessel itself and will favor following the path of least resistance which is the structural strength of the lattice of the material itself in the event of a failure. Now that is an experiment I would like to see followed up. Just because ............... dontchaknow !

I was going to respond to this the other week, then got too busy. Come back and wow, the posting has been changed and is now 3 times longer! Speelchucker, are you sure you aren't kidding yourself that you are definately weakening customers barrels when you flute them? I know you will do anything for money (you have admitted it in several postings before), but don't you think you may be opening yourself up for potential problems by providing an unnecessary and possibly disadvantageous machining operation on a customers rifle barrel? Regardless of whether you have stuck an L on their forhead or not? Don't know if the judge will see the funny side of that.....

I was going to give you the other half box of beer on the grounds of pure entertainment value alone, but then you wanted to double down on that bet. Well, i have to inform you that the slight swelling (from a possible dirt blockage) was about 1/2 from muzzle in the unfluted portion, but the rupture point definately did seem to occur back about 1 1/2" to 2" further back at the end of the flutes - right where the web thickness was at it's weakest. The distortion in the two parts of the barrel showed that the barrel had started to split at the flute section then forward and aft of this point. (Forward through the unfluted part towards the muzzle, and back down the length of the barrel following the path of least resistance - the flute channel). Whether this is able to be argued away as being beyond the intended reasonable pressure/proof requirements would probably be a matter for the courts. But either way, i'm confident that the results of this situation would not have been as dramatic if the barrel had not been fluted. Sorry but you lose the bet. No Beer.

Well Dean, they may not have taught you this, but having a thicker barrel does not mean that you can pound in more powder. There are maximum pressure limits that you are supposed to adhere to. I think you might be surprised to find that if you take a number 1 Shilen conture barrel and then take a Shilen number 5.5 barrel and flute the 5.5 so that the bottom of the flutes match the outside profile of the number 1 Shilen they will probably burst at approximately the same pressure. I must also add that the pressure at which both will burst, will be FAR beyond the recommended and excepted operating pressure of the firearm. They both have the same minimum wall thickness. It's not to hard to understand. I can call Shilen and ask them? Would that make you happy? And for that matter I don't think any of the manufacturers would flute barrels if there were any hazards involved in it. Also, all of the custom barrel manufactures offer their products pre fluted to gunsmiths and they don't seam to concerned. So, despite your warnings I sort of think that myself, and the rest of the gunsmiths who frequent this forum will probably continue to flute barrels. Despite your grave concerns which we have duely noted.

As for not working for idiots. I think that's self explanatory. I prefer to send the idiots to the gunsmiths that I happen to dislike. If you are so hard up for work that you have to work for door knobs. Well, I think that should tell you something.

As far as the split in the picture. I still say the split started in the unfluted portion because splits almost always start right at the bulge and if the split starts in the flutes it generally always stops when it reaches an unfluted part of the barrel. But we will never know for sure so its a pointless argument. And, as soon as the courts find out that there is a bulge in the barrel they will toss the case out of court. If I was silly enough to shoot a gun with a plugged bore I certainly wouldn't be stupid or crooked enough to try to sue anyone for damages. One of the first things they teach in hunter and firearms training is to make sure the bore is clear. They drum this into people for good reason. Stepping in front of a train and trying to sue them because they didn't stop only proves that you happen to be an idiot.

At any rate I have said it before and I'll say it again: "you're an inspiration to us all Dean" keep up the good work and be careful of that New Zealand sun. Maybe try a hat.