Gunsmithing Barrel Fluting
- Thread starter rowcifer
- Start date
Re: Barrel Fluting
You might give this link a try, click on barrel weight calc program.
http://www.riflebarrels.com/products/software.htm
You might give this link a try, click on barrel weight calc program.
http://www.riflebarrels.com/products/software.htm
Re: Barrel Fluting
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: rowcifer</div><div class="ubbcode-body">How much is a barrels weight reduced from fluting? Lets say the barrel is a 20". </div></div>
Not enough to matter.
Id like to hear the thoughts on fluting from some very respected barrel makers.
It may be an important topic.
I think the cons out way the pros by a ton. The only positive I see to fluting is looks. And I honestly dont even like the way they look anymore. If you need to save weight that bad, there are better ways.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: rowcifer</div><div class="ubbcode-body">How much is a barrels weight reduced from fluting? Lets say the barrel is a 20". </div></div>
Not enough to matter.
Id like to hear the thoughts on fluting from some very respected barrel makers.
It may be an important topic.
I think the cons out way the pros by a ton. The only positive I see to fluting is looks. And I honestly dont even like the way they look anymore. If you need to save weight that bad, there are better ways.
Re: Barrel Fluting
I have a couple with shallow flutes. I really don't think they make a damn bit of difference in how the rifle shoots. I also don't think they cool any faster either.
Bolt fluting is probably more functional than barrel fluting.
I have a couple with shallow flutes. I really don't think they make a damn bit of difference in how the rifle shoots. I also don't think they cool any faster either.
Bolt fluting is probably more functional than barrel fluting.
Re: Barrel Fluting
i'd guess 1/2 to 1 lb depending on the number/size/shape of flutes.
i feel if you are starting from scratch, a different barrel contour could weigh the same as a larger fluted barrel, cost less and still be more than accurate enough for a tac type rifle. if you are trying to loose weight from an existing rifle, fluting may be something to look into.
i'd guess 1/2 to 1 lb depending on the number/size/shape of flutes.
i feel if you are starting from scratch, a different barrel contour could weigh the same as a larger fluted barrel, cost less and still be more than accurate enough for a tac type rifle. if you are trying to loose weight from an existing rifle, fluting may be something to look into.
Re: Barrel Fluting
If you get a barrel from say, anyone. And you flute it in your shop on your mill, do you send it out for lapping or anything afterwards? Do you think it matters?
What if the barrel is a #3? Do you think you can crush its thin walls at all? Think that bore is still within .0001" like Shilen says their Select Match SS hand lapped barrels are?
From Shilen site: "To meet Select Match Grade criteria, the groove diameter must air gauge within .0003" of our standard diameter. Moreover, the uniformity of the bore cannot vary more than .0001" for the entire length of the barrel."
Think thats still the case after fluting? The walls of the barrel vary all the way down it, theres rifling the side cutter has to pass 100 times as it goes down the barrel...Theres a lot to think about.
If you get a barrel from say, anyone. And you flute it in your shop on your mill, do you send it out for lapping or anything afterwards? Do you think it matters?
What if the barrel is a #3? Do you think you can crush its thin walls at all? Think that bore is still within .0001" like Shilen says their Select Match SS hand lapped barrels are?
From Shilen site: "To meet Select Match Grade criteria, the groove diameter must air gauge within .0003" of our standard diameter. Moreover, the uniformity of the bore cannot vary more than .0001" for the entire length of the barrel."
Think thats still the case after fluting? The walls of the barrel vary all the way down it, theres rifling the side cutter has to pass 100 times as it goes down the barrel...Theres a lot to think about.
Re: Barrel Fluting
I've done my own fluting for over 15 years. Not a single problem that could be traced back to fluting. I use primarily Hart, Lilja, Kreiger and Bartien barrels.
Fluting factory barrels is not worth the risk.
I've fluted down to #2 hunting barrels. Got about 2 1/2 ozs out of that one. I've fluted up to 1.850" diameter barrels. That was measured by the number of scoops with the dust pan when I swept up.
What does fluting do.
1. reduces the weight of the barrel
2. increases the surface area
3 changes the balance of the rifle
4. adds a lot of sex appeal to the rifle
What's important.
1. balance
2. sex appeal
I may have those reversed.
I've done my own fluting for over 15 years. Not a single problem that could be traced back to fluting. I use primarily Hart, Lilja, Kreiger and Bartien barrels.
Fluting factory barrels is not worth the risk.
I've fluted down to #2 hunting barrels. Got about 2 1/2 ozs out of that one. I've fluted up to 1.850" diameter barrels. That was measured by the number of scoops with the dust pan when I swept up.
What does fluting do.
1. reduces the weight of the barrel
2. increases the surface area
3 changes the balance of the rifle
4. adds a lot of sex appeal to the rifle
What's important.
1. balance
2. sex appeal
I may have those reversed.
Re: Barrel Fluting
Fluting factory barrels is not worth the risk.
What does fluting do.
1. reduces the weight of the barrel
2. increases the surface area
3 changes the balance of the rifle
4. adds a lot of sex appeal to the rifle
What's important.
1. balance
2. sex appeal
I may have those reversed. [/quote]
Fluting can relieve residual stress in a barrel. Properly made, there should be very little to no stress in the steel of the barrel. If done properly, by a competent machinist on good equipment with a good set-up, fluting should have no effect on accuracy.
If Bubba pulls out his dremel and tries to "git-r-dun" you are going to have problems.
Fluting factory barrels is not worth the risk.
What does fluting do.
1. reduces the weight of the barrel
2. increases the surface area
3 changes the balance of the rifle
4. adds a lot of sex appeal to the rifle
What's important.
1. balance
2. sex appeal
I may have those reversed. [/quote]
Fluting can relieve residual stress in a barrel. Properly made, there should be very little to no stress in the steel of the barrel. If done properly, by a competent machinist on good equipment with a good set-up, fluting should have no effect on accuracy.
If Bubba pulls out his dremel and tries to "git-r-dun" you are going to have problems.
Re: Barrel Fluting
How does fluting effect the bore?
If the barrel isnt lapped after fluting, could it effect bore consistency?
If you took a piece of barrel steel, drilled it, fluted it, THEN reamed it, then cut rifled it, I can see how it would have zero effect. But doing it to a finished barrel, how does it not change anything in the bore?
I'm not saying the change would hurt accuracy. Just thinking it might happen.
Contouring effects the bore but theres no easy way around that.
How does fluting effect the bore?
If the barrel isnt lapped after fluting, could it effect bore consistency?
If you took a piece of barrel steel, drilled it, fluted it, THEN reamed it, then cut rifled it, I can see how it would have zero effect. But doing it to a finished barrel, how does it not change anything in the bore?
I'm not saying the change would hurt accuracy. Just thinking it might happen.
Contouring effects the bore but theres no easy way around that.
Re: Barrel Fluting
Just a note here, I have been able to shoot a UK made AIAW barrel that was fluted and shortened by Dave Tooley after it had around 2400 rounds on it. It shot just as good as before the work was done. I think this is possiable b/c it is a cut barrel, I think the game changes on a button rifled or hammer forged.
Just a note here, I have been able to shoot a UK made AIAW barrel that was fluted and shortened by Dave Tooley after it had around 2400 rounds on it. It shot just as good as before the work was done. I think this is possiable b/c it is a cut barrel, I think the game changes on a button rifled or hammer forged.
Re: Barrel Fluting
Personally, I am a fan of fluting. Mainly for weight reduction. I have no desire to tote a 13# rifle on a hunt. I have a couple of fluted barrels by Pac-Nor in my safe that shoot great.
If you can properly turn the profile of a blank after the bore is done without causing issues, why would fluting cause any issues when done properly?
Personally, I am a fan of fluting. Mainly for weight reduction. I have no desire to tote a 13# rifle on a hunt. I have a couple of fluted barrels by Pac-Nor in my safe that shoot great.
If you can properly turn the profile of a blank after the bore is done without causing issues, why would fluting cause any issues when done properly?
Re: Barrel Fluting
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: AZPrecision</div><div class="ubbcode-body">How does fluting effect the bore?
If the barrel isnt lapped after fluting, could it effect bore consistency?</div></div>
You're not taking out that much material when finish lapping. If fluting changed to bore that much, you already have a problem on you hands.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: AZPrecision</div><div class="ubbcode-body">If you took a piece of barrel steel, drilled it, fluted it, THEN reamed it, then cut rifled it, I can see how it would have zero effect. But doing it to a finished barrel, how does it not change anything in the bore?
I'm not saying the change would hurt accuracy. Just thinking it might happen.
Contouring effects the bore but theres no easy way around that. </div></div>
If there is any residual stress in the steel, it will show up in contouring. Then it becomes scrap. Otherwise its good to go and it doesn't really matter when you flute or finish lap.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: AZPrecision</div><div class="ubbcode-body">How does fluting effect the bore?
If the barrel isnt lapped after fluting, could it effect bore consistency?</div></div>
You're not taking out that much material when finish lapping. If fluting changed to bore that much, you already have a problem on you hands.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: AZPrecision</div><div class="ubbcode-body">If you took a piece of barrel steel, drilled it, fluted it, THEN reamed it, then cut rifled it, I can see how it would have zero effect. But doing it to a finished barrel, how does it not change anything in the bore?
I'm not saying the change would hurt accuracy. Just thinking it might happen.
Contouring effects the bore but theres no easy way around that. </div></div>
If there is any residual stress in the steel, it will show up in contouring. Then it becomes scrap. Otherwise its good to go and it doesn't really matter when you flute or finish lap.
Re: Barrel Fluting
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Hntbambi</div><div class="ubbcode-body">Personally, I am a fan of fluting. Mainly for weight reduction. I have no desire to tote a 13# rifle on a hunt. I have a couple of fluted barrels by Pac-Nor in my safe that shoot great.
If you can properly turn the profile of a blank after the bore is done without causing issues, why would fluting cause any issues when done properly? </div></div>
devils advocate here, but for a hunting rifle, don't you think you could find a barrel contour that weighs the same as what ever fluted barrel you have now and still be more than accurate enough?
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Hntbambi</div><div class="ubbcode-body">Personally, I am a fan of fluting. Mainly for weight reduction. I have no desire to tote a 13# rifle on a hunt. I have a couple of fluted barrels by Pac-Nor in my safe that shoot great.
If you can properly turn the profile of a blank after the bore is done without causing issues, why would fluting cause any issues when done properly? </div></div>
devils advocate here, but for a hunting rifle, don't you think you could find a barrel contour that weighs the same as what ever fluted barrel you have now and still be more than accurate enough?
Re: Barrel Fluting
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: shoot4fun</div><div class="ubbcode-body"> I also don't think they cool any faster either.
</div></div>
Wrong. It increases the surface area, so therefore it must increase the amount of heat lost (to the air) via convection.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: shoot4fun</div><div class="ubbcode-body"> I also don't think they cool any faster either.
</div></div>
Wrong. It increases the surface area, so therefore it must increase the amount of heat lost (to the air) via convection.
Re: Barrel Fluting
If we poke a hole in something and put a feature in it (rifling for instance) we depend upon the parent material to remain dimensionally stable during changes in temperature. This will happen by and large for most barrels.
All material has some level of "pent up aggression" in it as a product of manufacturing. Normalizing/stress releiving are two words describing the same process. Through careful change in temp (be it hot or cold) we make the effort to relax the material so that it doesn't exibhit weird behavior during machining or while in use.
A cut rifled barrel removes a chip. This also stress relieves or normalizes. Think of steel as a ball of rubber bands. When you start chewing on it its essentially like snipping at the individual bands. You take away some stress but the underlayment still has it.
A button barrel pushes the material into shape. This will induce a stress in the material.
The big difference is the procedure of when the normalizing process takes place. Its different for the two methods of manufacturing.
The wives tale/rule used to be don't eff with the contour on a button barrel. Do whatever you want on a cut barrel.
I think its been proven this is a myth. David Tooley is a sharp ol cat. I've personally only fluted two barrels in my life. Both were acts of desparation to make weight in a particular class and both guns performed beyond expectation.
This leads me to think the PROCESS is more important. If you use a sharp tool, a good fixture, and understand metalworking then I don't think it matters.
If your a trainwreck in a machine shop then you'll always be one and your work will reflect accordingly.
C.
If we poke a hole in something and put a feature in it (rifling for instance) we depend upon the parent material to remain dimensionally stable during changes in temperature. This will happen by and large for most barrels.
All material has some level of "pent up aggression" in it as a product of manufacturing. Normalizing/stress releiving are two words describing the same process. Through careful change in temp (be it hot or cold) we make the effort to relax the material so that it doesn't exibhit weird behavior during machining or while in use.
A cut rifled barrel removes a chip. This also stress relieves or normalizes. Think of steel as a ball of rubber bands. When you start chewing on it its essentially like snipping at the individual bands. You take away some stress but the underlayment still has it.
A button barrel pushes the material into shape. This will induce a stress in the material.
The big difference is the procedure of when the normalizing process takes place. Its different for the two methods of manufacturing.
The wives tale/rule used to be don't eff with the contour on a button barrel. Do whatever you want on a cut barrel.
I think its been proven this is a myth. David Tooley is a sharp ol cat. I've personally only fluted two barrels in my life. Both were acts of desparation to make weight in a particular class and both guns performed beyond expectation.
This leads me to think the PROCESS is more important. If you use a sharp tool, a good fixture, and understand metalworking then I don't think it matters.
If your a trainwreck in a machine shop then you'll always be one and your work will reflect accordingly.
C.
Re: Barrel Fluting
This is a question I could ask Shilen , but does anyone know if they offer fluted select match barrels? ... With the same .0001" guarantee?
If so, two things...
1)I'd have no concerns using one then. Its fluting it myself I have concerns with because I have no way to measure barrels or lap them.
2)Do they lap after fluting or before?
I just think that if someone needs to save weight, turning the barrel to a slightly smaller OD is the way to go. I can picture the chip pile left from fluting a barrel. It wouldnt weigh much.
As far as cooling, I dont have enough experience with shooting fluted barrels to tell.
This is a question I could ask Shilen , but does anyone know if they offer fluted select match barrels? ... With the same .0001" guarantee?
If so, two things...
1)I'd have no concerns using one then. Its fluting it myself I have concerns with because I have no way to measure barrels or lap them.
2)Do they lap after fluting or before?
I just think that if someone needs to save weight, turning the barrel to a slightly smaller OD is the way to go. I can picture the chip pile left from fluting a barrel. It wouldnt weigh much.
As far as cooling, I dont have enough experience with shooting fluted barrels to tell.
Re: Barrel Fluting
I know some of the benchrest crowd who use Shilens will get the unlapped contoured blank, have them fluted and then return them to Shilen for lapping. Does it help. I doubt it. I would bet that Ed has a story to tell about a bunch of barrels he had to eat in the old days. He told me this same thing in 1982 in Knoxville. That's how far back this goes.
Honestly guys this is much to do about nothing. Maybe in the old days of inconsistant steel there were surprises along the way. Expensive surprises for the barrel maker if one heat of steel acted totaly different than the last but these days the steel is a lot better. Better being uniform from lot to lot. Also every quality barrel maker out there understands what is required to turn out a match grade barrel. There are no short cuts, compettiton is good thing and makes everyone work harder.
Any stress relieved barrel either buttoned or cut can be fluted with flutes of a reasonable depth with little to no risk of accuracy issues.
I'm fluting 20 barrels for Accuracy International right now and will not lose one minute of sleep worrying about the accuracy of those barrels. It's a nonevent. It will never ever show up on the target. My 308's pound out 3/8" groups with factory ammo on a regular basis with fluted cut or buttoned barrels. I don't see the problem?
Seems like those that don't acutually do the work want to point, pick and stir the pot. I wonder how many of them have ever pushed a lead slug down a barrel?
As I said before I wouldn't flute a factory barrel. That's where there would a few surprises.
I know some of the benchrest crowd who use Shilens will get the unlapped contoured blank, have them fluted and then return them to Shilen for lapping. Does it help. I doubt it. I would bet that Ed has a story to tell about a bunch of barrels he had to eat in the old days. He told me this same thing in 1982 in Knoxville. That's how far back this goes.
Honestly guys this is much to do about nothing. Maybe in the old days of inconsistant steel there were surprises along the way. Expensive surprises for the barrel maker if one heat of steel acted totaly different than the last but these days the steel is a lot better. Better being uniform from lot to lot. Also every quality barrel maker out there understands what is required to turn out a match grade barrel. There are no short cuts, compettiton is good thing and makes everyone work harder.
Any stress relieved barrel either buttoned or cut can be fluted with flutes of a reasonable depth with little to no risk of accuracy issues.
I'm fluting 20 barrels for Accuracy International right now and will not lose one minute of sleep worrying about the accuracy of those barrels. It's a nonevent. It will never ever show up on the target. My 308's pound out 3/8" groups with factory ammo on a regular basis with fluted cut or buttoned barrels. I don't see the problem?
Seems like those that don't acutually do the work want to point, pick and stir the pot. I wonder how many of them have ever pushed a lead slug down a barrel?
As I said before I wouldn't flute a factory barrel. That's where there would a few surprises.
Re: Barrel Fluting
The thing that has come to mind when I have had customers ask for fluting is: is it worth it?
As Chad hit on all materials carry inherent stresses. Cut a piece of round stock and in some materials you can actually see the stress patterns in the fresh cut. Any removal of stock will affect those stresses. Is it enough to affect a rifles accuracy? I don't know for sure, that is a question best answered by a metallurgist or some of the barrel manufacturers.
Unless you are running a flood cooling system I would also think that localized heat build up could be a source of concern. Reprofiling is going to induce some heat as well but that is going to be evenly induced.
I would think it could also change the harmonics of the barrel. Any time a surface has a change in plane, stiffness is increased and I would believe that fluting would definitely have an impact on the harmonics.
I have reprofiled a few bull AR barrels and the feedback from the customers has been that the group size was reduced some. Whether that was a function of the new profiling or recrowning I can't say, I don't have enough data to say.
I am pretty new to the precision rifle game and may be totally off base but those are the thoughts that come to mind.
The thing that has come to mind when I have had customers ask for fluting is: is it worth it?
As Chad hit on all materials carry inherent stresses. Cut a piece of round stock and in some materials you can actually see the stress patterns in the fresh cut. Any removal of stock will affect those stresses. Is it enough to affect a rifles accuracy? I don't know for sure, that is a question best answered by a metallurgist or some of the barrel manufacturers.
Unless you are running a flood cooling system I would also think that localized heat build up could be a source of concern. Reprofiling is going to induce some heat as well but that is going to be evenly induced.
I would think it could also change the harmonics of the barrel. Any time a surface has a change in plane, stiffness is increased and I would believe that fluting would definitely have an impact on the harmonics.
I have reprofiled a few bull AR barrels and the feedback from the customers has been that the group size was reduced some. Whether that was a function of the new profiling or recrowning I can't say, I don't have enough data to say.
I am pretty new to the precision rifle game and may be totally off base but those are the thoughts that come to mind.
Re: Barrel Fluting
I agree that harmonics change. The larger the contour the less it can be affected. The smaller the more it can be affected.
As far the heat having an affect on a barrel. If there were enough heat generated to affect the barrel your cutting tools would be ruined and things would grind to a halt in a cloud of smoke. Depending humidity when I flute a barrel blank will either be cooler than the ambient temperature or just slightly warm to the touch, as in just over 100 degrees. I've got an infrared theremometer, I'll take some temp readings today and report back. Heat would be the last thing I would be worrying about. I would worry more about dull cutters and getting to close to the bore.
Is fluting worth it? Beauty is in the eye of the beholder.
I agree that harmonics change. The larger the contour the less it can be affected. The smaller the more it can be affected.
As far the heat having an affect on a barrel. If there were enough heat generated to affect the barrel your cutting tools would be ruined and things would grind to a halt in a cloud of smoke. Depending humidity when I flute a barrel blank will either be cooler than the ambient temperature or just slightly warm to the touch, as in just over 100 degrees. I've got an infrared theremometer, I'll take some temp readings today and report back. Heat would be the last thing I would be worrying about. I would worry more about dull cutters and getting to close to the bore.
Is fluting worth it? Beauty is in the eye of the beholder.
Re: Barrel Fluting
Dave don`t tell me that I am going to have to buy nitrous kits for my lathe and milling machine when I get them.LOL!
Dave don`t tell me that I am going to have to buy nitrous kits for my lathe and milling machine when I get them.LOL!
Re: Barrel Fluting
Ok I just fluted barrel and recorded temperatures.
Before fluting 71.2 degrees
after six flutes 13 1/2" long 74.6 degrees
bottom of flute 1" behind the cutter 78 degrees
cutter temp while cutting 98 degrees
heat <span style="font-weight: bold">No Problem</span>
Ok I just fluted barrel and recorded temperatures.
Before fluting 71.2 degrees
after six flutes 13 1/2" long 74.6 degrees
bottom of flute 1" behind the cutter 78 degrees
cutter temp while cutting 98 degrees
heat <span style="font-weight: bold">No Problem</span>
Re: Barrel Fluting
You don't need a nitrous kit but a mist system is nice to have and doesn't make as large a mess. More versatile for gun plumbers.
You don't need a nitrous kit but a mist system is nice to have and doesn't make as large a mess. More versatile for gun plumbers.
Re: Barrel Fluting
How about a medical nitrous kit with the mask.It is always easier to do something when you are HAPPY.
How about a medical nitrous kit with the mask.It is always easier to do something when you are HAPPY.
