Gunsmithing Flutting a Krieger Barrel

[nzgrip]

Getting a Krieger barrel for the rifle i'm building. I'm thinking about fluting it, is there anything that needs to be done after fluting? I'm planning to flute it myself on my mill.

Now i'm sure i'm gonna get the usual responses of leave it to a qualified gunsmith, so lets assume i can use my mill properly and machine the fluting correctly. Will it create any stress relieving issues or something else i'm not aware of on a Krieger?

 

[trilogymac]

Re: Flutting a Krieger Barrel

I did my Kreiger myself. VERY deep. No issues.

Not going to give you the "leave it to a qualified smith speech". It ain't rocket science.

Kept it cool with .035/pass.
Finish pass was .010.

Hope this helps.

 

[jrob300]

Re: Flutting a Krieger Barrel

triogymac,

Did you happen to do a before/after weight comparison?

John

 

[trilogymac]

Re: Flutting a Krieger Barrel

Almost a full LB reduction. There are 5 flutes 15" long with a 90 deg spiral. I used an involute gear cutter (very wide and squarer than what you normally see).

If you need more info, let me know.
Or, PM wnroscoe, he has seen it. I think I recall his reaction was "DAMN"!

Trilogymac

 

[hoguer]

Re: Flutting a Krieger Barrel

I was under the impression a Barrel should never be fluted post the bore being cut, due to stress/flex that is caused during the process. Thats why you order a barrel with flutes from the shop, so they flute it then cut the bore?

 

[jasonk]

Re: Flutting a Krieger Barrel

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ffhogue</div><div class="ubbcode-body">I was under the impression a Barrel should never be fluted post the bore being cut, due to stress/flex that is caused during the process. Thats why you order a barrel with flutes from the shop, so they flute it then cut the bore? </div></div>

I don't know the answer to all that, but I do know that I've had Rock flute barrels after the fact. Paul said that they hand lap them again after the fluting, but that could be a line to make the customer feel better, I'm not sure it makes a bit of difference.

Now I do think it could make a bigger difference on a hammer forged barrel vs a cut rifled one.

 

[hoguer]

Re: Flutting a Krieger Barrel

my Smith said he took a factory bull(i know, not the EXACT same) and did a straight flute down one side of the barrel as a example in a walk thru of his shop, to show the extreme flex the barrel experienced something like 1/32 or 64 (can remember for sure) of movement in the barrel, and post even fluting all of the opposing sides, it evened it back out to near perfect alignment, but it was NOT as straight.

 

[trilogymac]

Re: Flutting a Krieger Barrel

I believe you will find Kampfeld flutes after the fact ALOT.
GAP fluted a Rock barrel for me after the fact as well with NO ill effects. Rock Creek will do it after as well.

My understanding is the problems arise in button barrels but hopefully someone more knowledgable than me will chime in..

 

[Doug308]

Re: Flutting a Krieger Barrel

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ffhogue</div><div class="ubbcode-body">my Smith said he took a factory bull(i know, not the EXACT same) and did a straight flute down one side of the barrel as a example in a walk thru of his shop, to show the extreme flex the barrel experienced something like 1/32 or 64 (can remember for sure) of movement in the barrel, and post even fluting all of the opposing sides, it evened it back out to near perfect alignment, but it was NOT as straight. </div></div>

Would helical style flutes prevent distortion and make it the better type of fluting ?

 

[PCR]

Re: Flutting a Krieger Barrel

My understanding is that you can flute a cut rifled barrel after rifling, and you need to flute a button pulled barrel before rifling. Reason is because a button displaces metal inducing stress and fluting after can change or release stress.

I had a 300 win mag with a Schneider button pulled barrel that was fluted after. It shot mostly from .6" - 1", sometimes over an inch. I ended up having it lead lapped and was told there was a tight spot 6 inches from the muzzle. He lapped it out and that calmed it right down to a lot of .5 moa groups.

 

[nzgrip]

Re: Flutting a Krieger Barrel

Yeah i'm thinking that button pulled or hammer forged barrels would be a problem because of the processes inducing stresses in the barrel, but the i think the Kriegers are meant to be pretty much stress free with the cut rifling. But seeing as the barrel is gonna cost me around NZ$900 fitted ($700 for the barrel blank) i don't really want to fuck it up.

 

[Brutas]

Re: Flutting a Krieger Barrel

Fluting a cut rifled barrel after it has been rifled is fine. No stress is induced into the steel during the rifling process. Most Cut-riflers flute after rifling. A button barrel can not be flute before rifling, the blank needs to be concentric to handle the stress caused by swaging the rifling. Button barrels are then stress relieved, contoured etc..

Brian Birutas
Bartlein Barrels

 

[jasonk]

Re: Flutting a Krieger Barrel

^^^ I'd listen to this guy, I'll bet he knows ^^^

 

[jrob300]

Re: Flutting a Krieger Barrel

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Brutas</div><div class="ubbcode-body">A button barrel can not be flute before rifling, the blank needs to be concentric to handle the stress caused by swaging the rifling. Button barrels are then stress relieved, contoured etc.. </div></div>

So, once the button barrel is stress relieved, post-rifling processes affect it the same as a cut barrel? Does a final lapping have to take place after the fluting , or its GTG?

John

 

[PCR]

Re: Flutting a Krieger Barrel

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Brutas</div><div class="ubbcode-body"> A button barrel can not be flute before rifling, the blank needs to be concentric to handle the stress caused by swaging the rifling. Button barrels are then stress relieved, contoured etc..
</div></div>

thanks for the clarification

 

[RollingThunder51]

Re: Flutting a Krieger Barrel

..

Mark Penrod, huge rifled Lilja blank (rail is part of the barrel steel!). Octagon to round to fluted. Superb accuracy all work done post rifling. Odd two part photo, sorry. Just what Tri said slow and easy.

..

 

[nzgrip]

Re: Flutting a Krieger Barrel

Sweet, cheers guys.

 

[border_reiver]

Re: Flutting a Krieger Barrel

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Brutas</div><div class="ubbcode-body">Fluting a cut rifled barrel after it has been rifled is fine. No stress is induced into the steel during the rifling process. Most Cut-riflers flute after rifling. A button barrel can not be flute before rifling, the blank needs to be concentric to handle the stress caused by swaging the rifling. Button barrels are then stress relieved, contoured etc..

Brian Birutas
Bartlein Barrels
</div></div>

I've fluted cut barrels prior to reaming the bore, and after. Prefer to flute prior. Button or cut, make sure there is support under the cutting tool..

 

[stan462]

Re: Flutting a Krieger Barrel

That is a nice looking flute job