Barrel fluting

[JR FIREARMS]

Finally had chance to set the machine up for barrel fluting and test the new programs i’ve written. Straight and spiral will be offered, and interupted at some point later one (it’s alot harder to write the program). 
 

There are a few bugs to iron out and most testing, but so far so good  

[JR FIREARMS]

https://youtu.be/4x74Np-_zYo

 

Quick video of the fluting in action. 

[Scotch_egg]

The best fluting to my eye is Blaser’s varmint style. 
 

can you replicate it? 
 

what are the cost implications? 
 

obviously barrel profile and custom programs Will have implications. But an idea will give give confidence to ask. 
 

especially when it looks  good. 

[JR FIREARMS]

I’m not personally a fan of the Blaser fluting and it has never been requested.
 

But my current programs easily allow an increase in the flute quantity to have a similar look, but it wouldn’t flow into the swamp like the blaser. This would require a more complex and custom program for each barrel, and it would make it quite costly. 

[JR FIREARMS]

Here is mock up of the interrupted fluting pattern. 

[weejohn]

I do like interrupted fluting 

[JR FIREARMS]

On 11/25/2020 at 9:38 PM, weejohn said:

I do like interrupted fluting 

The more i see it the more i like it. 

[JR FIREARMS]

A little more testing done. Tool paths are all good, i just want to enhance the tool holding and support. 

[Richie88]

Guys how much would this cost on a T3X 24” barrel?

[JR FIREARMS]

I’ll only flute custom barrels, no factory barrels. They have a tendency to warp. 

[Chris-NZ]

Hundreds of Tikkas done here with no ill effects. My gunsmith buddy uses a CNC mill and once you get the carbide cutter speed and feed rate right, the cutter cuts very smoothly and can do a lot of barrels. His last cutter didn't wear out but was killed by a sudden mains blackout. Surprisingly, Tikkas despite having a hammer forged barrel don't seem to grow the bore diameter measurably under fluting unlike many buttoned barrels.

No matter what barrel gets fluted, it's going to release some degree of stress I guess.

[lapua]

8 hours ago, JR FIREARMS said:

I’ll only flute custom barrels, no factory barrels. They have a tendency to warp. 

There’s a Remington barrel in one of the pictures, was that just practice?

[No i deer]

Mik Mak at Dolphin precission may flute it for you 🤔

[JR FIREARMS]

1 hour ago, lapua said:

There’s a Remington barrel in one of the pictures, was that just practice?

Yes that is juts a practice piece, which also developed a 1mm bow in the middle due to stress relieving. Had that been a customers barrel it would now be scrap. 

[JR FIREARMS]

2 hours ago, Chris-NZ said:

Hundreds of Tikkas done here with no ill effects. My gunsmith buddy uses a CNC mill and once you get the carbide cutter speed and feed rate right, the cutter cuts very smoothly and can do a lot of barrels. His last cutter didn't wear out but was killed by a sudden mains blackout. Surprisingly, Tikkas despite having a hammer forged barrel don't seem to grow the bore diameter measurably under fluting unlike many buttoned barrels.

No matter what barrel gets fluted, it's going to release some degree of stress I guess.

Yes you may get away fluting 99% of factory barrels, but why risk ruining a customers barrel for the sake of profit. The first barrel in the pictures suffered severe stress relieving, and is a perfect example of why not to do it. Although it would now be handy for shooting round corners 😂
 

Although any material could stress relieve, custom barrels undergo a special heat treatment and stress relieving process. Combine this with the much less stressful machining process of button or cut rifling, it is highly unlikely to happen. If it was of any potential concern then the barrel manufacturers wouldn’t offer fluting themselves. But it is important not to flute too deep. 

[Chris-NZ]

A "bowed" barrel isn't necessarily any issue. Very few barrels are drilled dead straight and it even if they aren't, it doesn't seem to affect accuracy. My gunsmith had a batch of Bartleins, one of which was dead straight and the other a pronounced curve in the bore. The bent one clearly outshot the perfect one despite identical chambering. My son's FTR rifle has a 32" Broughton which was left over from a batch of barrels brought in for NZ team rifles. It wasn't used as it had an obvious curve in the bore. Anyway, it was eventually fitted to my old RPA CG-2000 with the curve indexed up and that thing is a -real- tackdriver.

 

 

[JR FIREARMS]

Agreed that a curve in the bore is quite common and not likely to cause issues if chambered correctly. But this barrel physically bowed/bent as a result of removing material. So you would be unlikely to get the shots on target at distance, you’d run out of scope adjustment. 
 

Tikkas/Sakos may be better than others, but I personally don’t see why anyone would risk ruining a rifle for the sake of it. 

[Ronin]

Not sure there is any merit in fluting a factory barrel 

Essentially spending doubly what the barrels worth on cosmetic upgrade 

Certainly worth considering for replacement barrel off the action though

 

[No i deer]

What's the difference between fluting a custom barrel blank or a factory barrel..?

[JR FIREARMS]

45 minutes ago, No i deer said:

What's the difference between fluting a custom barrel blank or a factory barrel..?

Nearly all factory barrels are hammer forged, this induces stresses into the steel. When you machine the barrel with something like fluting or re-profiling, those stresses can release. This can cause swelling in the bore diameter or physical bending/warping of the barrel. This may not always cause accuracy issues, but you can get other issues such as running out of scope adjustment because the barrel is trying to shoot round a corner. 
 

Custom barrels are normally either cut rifled or button rifled, this imparts little to no stress in the steel. They also tend to undergo better heat treatment processes to relieve stresses in the steel. So when you profile or flute them the chance or causing issues is virtually zero. 

[JR FIREARMS]

1 hour ago, Ronin said:

Not sure there is any merit in fluting a factory barrel 

Essentially spending doubly what the barrels worth on cosmetic upgrade 

Certainly worth considering for replacement barrel off the action though

 

😂 very true. The money would be better spent on a new barrel or bolt fluting 😎

I’ve always read/hears about varying degrees of factory barrels stress relieving, and witnessed it with small muzzle threads on large bore calibres. But it was interesting to see first hand just how badly it can happen! Had this old Rem barrel been a customers rifle, it would be ruined. Unless there is a new competition that involves shooting round corners 🤣

[No i deer]

Ok thanks for the info.

Maybe one of the reasons most factory barrels are plain besides the extra cost of the fluting..

I've had a 6.5-06 with a 26 inch deep fluted armalon hammer forged barrel and it shot great..

After 2500 shots I had 2 consecutive 630yds rabbits the same week it went off for a 284 rebarrel.

[JR FIREARMS]

It may well be one of the reasons. Obviously it can be done, but we’ll never know how many get rejected or what process they follow. Or just not bother checking and let it ship. It’s not uncommon to hear of people with factory rifles that don’t shoot, or can’t get the shot on paper as they run out of adjustment etc. 

[Leeman]

11 hours ago, JR FIREARMS said:

. 
 

Custom barrels are normally either cut rifled or button rifled, this imparts little to no stress in the steel. They also tend to undergo better heat treatment processes to relieve stresses in the steel. So when you profile or flute them the chance or causing issues is virtually zero. 

I would disagree with that statement, button rifling imparts serious stresses within the barrel steel, that's why most custom button rifled barrels are stress relieved two to three times.

[JR FIREARMS]

36 minutes ago, Leeman said:

I would disagree with that statement, button rifling imparts serious stresses within the barrel steel, that's why most custom button rifled barrels are stress relieved two to three times.

Button rifling will of course induce stress, but not as much as cold hammer forging, that’s what i more referring to 🙂. Once button barrels are stress relieved correctly very little stress remains that will be of any major concern. Where as hammer forged will always have stresses remaining, and often bad enough to cause issues.