Why not flute the last few inces on muzzle end?
- Thread starter fe1
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In the 2001 issue of PS magazine, Jerry Stiller (Stiller Precision Firearms) wrote an article titled "The Real Story on Barrel Fluting". From the article: It is his opinion that if you are buying a new barrel, the only reason to flute is to make it cool slightly better or make it look cool. He says "There are other risks associated with fluting, such as stress relief of the blank and changing the bore shape/size. He goes on to say "However,I feel the structural risks are fairly low, as long as the CHAMBER AREA AND THE LAST 2 INCHES OF THE BARREL ARE LEFT UNFLUTED" (Emphasis in caps are mine).
So, my interpretation is that the last couple inches of the muzzle end is the last place you want ANY uncontrollable change in bore size/shape ( I say "uncontrollable" because some barrel makers (Kreiger for one) put a slight choke in the muzzle through the lapping procedure). Also, on the chamber end I can see where the metal can get dangerously thin depending on the contour, how close the flutes are to the chamber, and the depth of the flutes.
So, my interpretation is that the last couple inches of the muzzle end is the last place you want ANY uncontrollable change in bore size/shape ( I say "uncontrollable" because some barrel makers (Kreiger for one) put a slight choke in the muzzle through the lapping procedure). Also, on the chamber end I can see where the metal can get dangerously thin depending on the contour, how close the flutes are to the chamber, and the depth of the flutes.
To add another scenario for you. I think it would be difficult to recrown a barrel at has flutes all the way to the end of the muzzle? I'm not a gun smith but, I can imagine it would make that task difficult at best with flutes present!
Mike
Mike
Hi,
I am going to surprise more than one on that post, but yes you can have your barrel fluted to the end.
I have a lothar barrel on a sako in 308. The barrel is close to a number4 contour with 8 flutes. I even got my local gunsmith to thread it a M14x1 to fit a suppressor on it.
Accuracy is still good for a barrel that shot more than 3000 rounds.
It shoots federal factory load and subsonic loads under an inch.
As fare as recrowning is concerned, if you use the spider method with an indicating rod to dial in your barrel there is no issues.
Otherwise you can turn a sacrificing collar that can be glued with cyanoacrylate close to the muzzle end.
True the sacrificing collar and set it up in a steady rest so you can do your crown easily.
Nic.
I am going to surprise more than one on that post, but yes you can have your barrel fluted to the end.
I have a lothar barrel on a sako in 308. The barrel is close to a number4 contour with 8 flutes. I even got my local gunsmith to thread it a M14x1 to fit a suppressor on it.
Accuracy is still good for a barrel that shot more than 3000 rounds.
It shoots federal factory load and subsonic loads under an inch.
As fare as recrowning is concerned, if you use the spider method with an indicating rod to dial in your barrel there is no issues.
Otherwise you can turn a sacrificing collar that can be glued with cyanoacrylate close to the muzzle end.
True the sacrificing collar and set it up in a steady rest so you can do your crown easily.
Nic.
From what I've read here its my understanding that its not good for accuraccy to chop the length of a barrel from the muzzle end, Right?
For example chopping a 30" standard palma to a 24" from the muzzle end of a barrel. Especially if the muzzle is choked from the maker.BTW it is a Kreiger Barrel. The whole purpose of chopping it is portability.
I guess what I'm asking is,
Will chopping 6" off a 30" Kreiger barrell (or any barrel for that matter) from the muzzle end going to Degrade its accuraccy?
For example chopping a 30" standard palma to a 24" from the muzzle end of a barrel. Especially if the muzzle is choked from the maker.BTW it is a Kreiger Barrel. The whole purpose of chopping it is portability.
I guess what I'm asking is,
Will chopping 6" off a 30" Kreiger barrell (or any barrel for that matter) from the muzzle end going to Degrade its accuraccy?
No, as long as it is crowned properly.fe1 said:
The important thing is that the bore at the muzzle is tightest.
If you contour/flute a button rifled barrel after lapping, too near the muzzle, you risk opening to bore at the muzzle.
With cut rifled, there is way less(if any) risk.
With hammered (such as with a LW), the bore actually gets tighter with further contouring.
If you contour/flute a button rifled barrel after lapping, too near the muzzle, you risk opening to bore at the muzzle.
With cut rifled, there is way less(if any) risk.
With hammered (such as with a LW), the bore actually gets tighter with further contouring.
LHSMITH said:
Why? I do not know because I bought the rifle second hand already fluted. So that question would be for the precedent and unknown owner. All I know is that the rifle was built to compete in metallic silhouette shooting , so that owner might have wanted a barrel that could cool down quicker ?
The barrel is 24" long. Very soon, I m going to trim it down to 19" or 20" recrown and rethread it so that I have a more compact set up to manoeuvre in the New Zealand bush. I will keep you posted regarding the accuracy or the loss of any of it.
Hi Mikecr,mikecr said:
I will give you a few examples of things that go against what you just wrote.
Do not take it badly, I think a Lot of what you just wrote could be true especially in short distance br or to shoot the ass of a fly.
The choke on the bore seems to be important when shooting 22lr lead bullets, and I believe that the best br barrels out there are lapped that way because lead does not spring back . Once that bullet looses some of its material with the friction in the bore the only thing that can keep it exiting straight is that choke on the last few inches of the barrel.
With a jacketed bullet, the jacket may be "gliding " in the bore with out loosing so much material, so a bore with uniform and consistent dimension should be enough to guide it straight. I have seen tests performed on rifle where the accuracy actually increases as the barrel is cut down an inch at a time : ( there is a point where it reaches a nod and is t it's best with that test load and then groups reopen a bi after, but in no way are the groups opening bigger than when the barrel was shot at its original length).
In New Zealand, as well as UK, France and Scandinavia, a lot of factory rifles get their barrels fitted with after market sound moderators and the accuracy generally improves. I recently had a friend of mine who bought a second hand tikka varmint in 308. He got he barrel shorten by 2 inches and threaded at 1/2"x28: that means no much more than 2 mm of meat left either side of the bore at the muzzle! (I hate those small threads!) he fitted a suppressor on it and managed to produce several groups under 1/2 inch at 100 yards with factory hornady match Ammo. Go and figure out!
Regarding cut rifle barrels you are certainly right. One trick from barrel makers to get a uniform bore is to profile and cut the flutes after the blank of steel is gundrilled but before it is reamed out, that way they know the bore is very close to perfect in dimensions as the outside wont get touched again.
I believe Lothar Walther barrels are button rifled and not hammer forged.
Sako/ tikka ar hammer forged .
As to the hammer forged barrel bore getting tighter as the outside is contoured, maybe to a certain degree, but I have pushed some lead bullet through some 22 lr hammer forged barrels ( BSA and cz) and the further you push the lead to the muzzle end the looser you can feel the bullet slipping in the barrel. And funny enough, when pushing the lead bullet from the muzzle( the thin part of the barrel) back to the chamber( the thickest outside contour) you can feel the bullet getting tighter and tighter.
Again, I don't think I hold the truth, but these are a few real experiences that defy the general theory .
Nic
Well no doubt that adding factors to contour alone can lead to many possible results.
There are also excellent barrels out there(performance-wise) that are not lapped to any tapering of bore but touted instead as consistent from end to end. This still works to similar effect(if true), because pressure, which opens bores(locally tapering the bore along bullet travel), decreases further & further down the bore. This opening the bore less & less nearer the muzzle, effectively letting the muzzle be tightest in influence.
There are also excellent barrels out there(performance-wise) that are not lapped to any tapering of bore but touted instead as consistent from end to end. This still works to similar effect(if true), because pressure, which opens bores(locally tapering the bore along bullet travel), decreases further & further down the bore. This opening the bore less & less nearer the muzzle, effectively letting the muzzle be tightest in influence.
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