bullet stability

[timuhoh]

Several years ago I saw an article on a machine that spun a bullet and measured the stability or balance of the bullet.Does anyone know the name of this machine?

 

[Forum Boss]

Somebody may have made a spin balance tester. But I think you're thinking about the Juenke machine. It measures for voids and inconsistencies within a bullet.

Vern Juenke works out of a shop in Reno, Nevada called The Accuracy Den, http://www.theaccuracyden.com/

From Vern's web site:

"A simple explanation of how this unit works is as follows:

The ICC will electronically detect flaws that will cause the bullet to stray from the ideal path. By passing electromagnetic lines of force through the bullet or case, internal flaws are detected that would never be seen by using conventional testers. These internal flaws are measured and shown on the meter display.

The bullet or case to be tested is placed on carbide balls on the units work plate. A drive rubber on the motor drive shaft is placed on the test piece and the motor drive speed is adjusted as required to rotate the test piece to be tested for deviation units on the panel meter scale. Bullet jacket thickness variations, out of round, boat-tail to body concentricity, and ogive shape and form can be tested and evaluated by the electronics in the ball plate.

This is shown as deviation units by the movement of the pointer on the meter scale. The less the deviation units, the more perfect and balanced the bullet is. Case wall thickness variations at the head of the case forward of the solid head can also be tested."

 

[USAPatriot]

"Electromagnetic Lines of Force"? What in the world does that mean? I can only surmise that the guy is using ultrasound or some other radiated/reflected form of energy to probe a bullet's interior. Since copper and lead are non-ferrous metals, "electromagnetic lines of force" seems to have little meaning in anything short of an MRI. He could be measuring conduction but that would have little meaning. Just a thought. -Rod-

 

[mikecr]

Ultrasonic I think.
It'll show jacket thickness variance, just like measured brass thickness variance.
I can imagine bullets with best/matched internal quality, would be less likely to break from the pack.

 

[Preacher]

Vern Juenke's,bullet spinner) will make a believer out of you concerning the differences between custom bullets and the factory bullets, although the Nosler Ballistic tips seem to fare very well.

 

[sling_n_glove]

According to the description the thing uses a magnetic field, probably generated from a coil of wire with an electrical current running through it. It works because a magnetic field causes a charged particle that moves through it to behave differently than if there was no magnetic field. Also, the charged particle causes its own magnetic field. The copper and lead bullet has lots of charged particles,electrons) and rotating the bullet-under-test is what gives them the needed motion. It looks like the designer of the ICC uses the change in the magnetic field to detect variations in the construction of the bullet.

The detectors used by ballistic labs use a similar concept to detect the passage of a bullet through a point. There's a coil of wire energized by a current. When the bullet passes through the magnetic field, it can be detected very precisely. The strobes used to create those amazing photographs of bullets in flight can be triggered this way.

Sound is altogether different than electromagnetism, no matter how high the pitch, because sound is a mechanical phenomenon. It needs some kind of medium like air, water, a metal wire or bar or whatever. Electromagnetism is altgether different - it needs no medium other than the space it's in, though it will obviously conduct differently through certain things such as air, water, metal wires, etc.

The ICC looks really clever.