Calling all firearm engineers …

[HansV]

But will that cause you to explode?

[Leif]

Avoid rotating before you hit Leif!

Presumably Leif will rotate as he turns the other cheek

Comme ça?

[HansV]

That would certainly cause an explosive situation!

[ChrisGreaves]

According to Rifling: Basics

...if a bullet is simply ejected out of the barrel at high speed, any irregularities in its surface will cause the bullet to wobble and create turbulence in the air. This turbulence will quickly make the bullet deviate from a straight line and head off in some random direction. However, if a bullet rotates about its axis when flying in the air, the effect of any irregularities on its surface will be somewhat nullified due to its rotation...

Hi Stuart, and thanks for this.

I don't have a problem with rifling and spin per se. It was the justification in terms of energy that thwarted me.
It costs energy to make a projectile spin, and that energy must be taken away from the total energy available from the explosive charge, and hence taken away from the energy available for the linear kinetic energy.

Cheers
Chris.

P.S. My guess is that a spherical projectile would do away with much, but not all, of the concern about wobbling. Although I concede that the "balls" of, say, 300 years ago were probably nowhere near to being a perfect sphere!

[ChrisGreaves]

See, for instance, this classic reference.

Oh Goody! I was wondering how my Saturday night was going to turn out.
I'll take a shot at this after supper ...

[ChrisGreaves]

That would certainly cause an explosive situation!

And we now cross over to "Hoist with his own petard" ...

[AlanMiller]

It was the justification in terms of energy that thwarted me.
It costs energy to make a projectile spin, and that energy must be taken away from the total energy available from the explosive charge, and hence taken away from the energy available for the linear kinetic energy.

You still seem unconvinced. This is one calculation (without working) I was able to find:
75gr bullet shot at 3500 fps from a 1:10" barrel -> linear KE of 2766 Joules and a rotational KE of 7.6 J.
So that's about 0.3% of the total muzzle energy taken by rotation.

Alan

[LisaGreen]

Watch out you don't give him a funny turn!!!

Now there's a twist to the story!

Is all of this just spinning a yarn?

[AlanMiller]

This is all going round in circles.

Alan

[DaveA]

I have heard of spinning a story, but, you have really put a spin on this one.

[viking33]

Blessed are those who talk in circles, for they shall be called Wheels!

[ChrisGreaves]

You still seem unconvinced. This is one calculation (without working) ... So that's about 0.3% of the total muzzle energy taken by rotation. Alan

Thanks Alan.
I am convinced now, both by your given figures and by that excellent document you pointed out to me.
The core of the matter seems to be on pages 2-3 and 2-4.

I found what i thought were typos on pages 2-22 (inuzzle) and 2-29 (niuzzle) and then realized that the paper had probably be scanned by an early text-recognition product such as ZYImage, very popular in the early 90s. I taught a course in ZYImage.

In this vein I might say that I had a iiiaxiiiially interesting weekend!

Chris

[ChrisGreaves]

Blessed are those who talk in circles, for they shall be called Wheels!

LisaGreen, Alan, DaveA and viking33:

You're all fired!

One by one, in rotation.

Cheers
Chris

[viking33]

Blessed are those who talk in circles, for they shall be called Wheels!

LisaGreen, Alan, DaveA and viking33:

You're all fired!

One by one, in rotation.

Cheers
Chris

You can't fire us, we all resign!

[HansV]

It's a revolution!

[viking33]

It's a revolution!

That's OK, Hans.
I'm thinking of forming the Eileen's Lounge Protective Union. ( ELPU ) that will include Grandfathering of most memberships.

[AlanMiller]

You're all fired!

Rifling through my chambers, I learned that people of our calibre can't be muzzled like that.

Alan

[Rudi]

You're all fired!

Rifling through my chambers, I learned that people of our calibre can't be muzzled like that.

Alan

Masterfully put Alan!

[Rudi]

    
    

(Seems appropriate for this thread)

[stuck]

    
    (Seems appropriate for this thread)

Wouldn't a bullet point be more appropriate?