Barrel knots and accuracy

[bow]

I have no available MkVII balls and don't know where to looking for them. I reload Sierra and Hornady, sometimes available PRVI PARTIZAN but i find them less consistent . So handloading is a way to control barrel vibrations .. Jay Seets wrote that a gentlemen, Mr. F.G. Price experimentally located nodes and antinodes of a No.1 MkIII with heavy barrel. He found, following Jay Seets book, 8 nodes and 7 antinodes. Last but not least Sweet says that accurate location of those point tell us the location of packing.. It would be very interesting if we found "the experiment" Mr. Price used to locate nodes...

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[Peter Laidler]

To REALLY understand harmonics you need a degree in music believe it or not. Like vibration, harmonics is really a science in its own right.

[bow]

To REALLY understand harmonics you need a degree in music believe it or not. Like vibration, harmonics is really a science in its own right.

Mine is not an academic question...I could'n get total knowledge about this phenomenon, not being maths or phisics graduate. So i say: how could i locate the points where the barrel remains more stable during shoot? For me it's enough an empiric way to determine it. Only this.

[jss]

On this subject, are there any details around regarding the movement of the muzzle during firing. Presumably the vertical upward movement has been allowed for in the forend aperture design. I have a poorly fitting possibly bent forend on a No4 7.62 conversion which causes the muzzle to deflect left on upward movement but if the muzzle only moves a few thou upward in the forend aperture then does it matter and if so by how many minutes max?.

[Bruce_in_Oz]

Bow,

The information about nodes is certainly in James Sweet's book.

The only possible catch is that the data was derived using Mk7 ball ammunition. I do not know if anyone has ever tried to confirm the data using any other ammunition.

Also, "sporting" boat-tailed bullets are not recommended in orginal enfield bores. Such a bullet does not expand in the bore like the old open-based Mk7. Thus there is much greater potential for considerable gas bleed around the bullet. Bear in mind that MINT new Lee Enfield barrels can run out to as much as .320inches effective groove diameter, whilst bore diameter is generally held VERY close to the nominal .303 inch.

If the barrel is already a bit "pre-loved" and suffering from erosion caused by heavy use of cordite-fueled ammo, this gas bleed wil rapidly eat away at the thoat and start attacking the rifling lands.

[Peter Laidler]

The next obvious question then Bow is '....why do you want to do this experiment' The reason I ask is that the barrel is what it is and acts how it acts. The reason that it is the MUZZLE that is sound (or free to move but only in one controlled direction - up) is because it is the muzzle that is the very last part of the rifle that has any effect on the projectile before it is alone and free of all outside interference. I know that this is obvious but some people still don't understand this.

I know that someone is going to say next '....... just a minute, then why don't I just bind the muzzle so that it's solidly fixed then?' Good question... You COULD, but the barrel will still whip. And while cartridges are made the way they are and harmonics (it's that word again...) do what they do and vibration acts the way it does, we're stuck with it

Takes me back to teaching physics when sometimes you just have to tell the class that some things happen - or work, like hydraulic principles - because you can't defeat the laws of physics

[bow]

I agree with you Peter. It's more simple to follow physics laws than fighting against them ( fighting being impossible). I believe packin barrel nodes has a positive effect on barrel stiffening. Hence on grouping capability. But I'm an apprentice and i'm sure wrong. . . But thin No.1mkIII barrel were stiffened this way..
Sorry for my madness words!!