Spinning bullets for accuracy.

[allenn]

Why do bullets not spin on there center line. Does the point of the bullet wobble when it leaves the muzzle.

https://www.youtube.com/watch?v=uOUqy9G8s6Q

 

[Catskinner]

That's ok but I have a better way Junke easy to read

 

[allenn]

I also would like to know what the Juenke measures. From what I understand it measures a variation in the eddy currents produced by the jacket. If it does, the Juenke and the air spinner measure two different things. I think the air spinner would be more likely to measure total bullet imbalance.

 

[tonysnoo]

I'm curious. Why would you run air around the back of the bullet and expect the bullet to react the same as if was in flight. Couldn't the air tube be a smaller diameter and then the bullet could be inserted nose into the air?

It looks like it might be a cool test to see how consistent the boat tail is with the CL of the bullet...am I missing something?

 

[Outrider27]

The Juenke machine was/is essentially a micro balance checking device, like the machine used to spin up your car's wheels to establish how much and where balance weights need to be added, it just uses a different approach - it measures how far off center or if the jacket is centered around the bullet core (it will only work on copper jacketed lead core bullets as far as I know - it needs the copper/lead interface to key off). A dial indicator type comparator measures variations in the outside surface of the jacket. The Juenke machine measures variations in the jacket at the internal core/jacket boundary using an ultrasonic sensor - any variation indicates that the core is not centered in the jacket, which will raise hobb with the flight of a spinning bullet - if you find a bullet with a large variation and section it, you will find that while the core and jacket will (probably) be properly bonded, the jacket will be noticeably thicker on one side of the core than the other, creating a significant imbalance in flight. The way ultrasound is used in this device does not allow detection of another type of problem that will cause imbalance in flight, a void or bubble in the lead core. It is possible to detect such voids, but the ultrasonic machine that does so is totally different in concept and use and not generally found outside of the inspection departments of large industrial facilities - it's a pricey little devil capable of detecting voids or measuring wall thickness in metallic assemblies, depending on how it's calibrated for the specific job.

Hope the above helps a little.

Mike

 

[allenn]

Tonysnoo, good question. I'm not sure if the bullet acts the same in flight as it does spinning in air, but my guess is it would be close. I have put the bullets in point down and point up. They still wobble so I just put them in point up.
No your not missing something. I have spun hundreds of bullets and have yet to find one that will spin on it's CL of the bullet. But there is a difference in the readings that I get. I suspect some are more balanced or the CL of the bullet is closer to the actual center than others.

 

[Catskinner]

The Juenke machine was/is essentially a micro balance checking device, like the machine used to spin up your car's wheels to establish how much and where balance weights need to be added, it just uses a different approach - it measures how far off center or if the jacket is centered around the bullet core (it will only work on copper jacketed lead core bullets as far as I know - it needs the copper/lead interface to key off). A dial indicator type comparator measures variations in the outside surface of the jacket. The Juenke machine measures variations in the jacket at the internal core/jacket boundary using an ultrasonic sensor - any variation indicates that the core is not centered in the jacket, which will raise hobb with the flight of a spinning bullet - if you find a bullet with a large variation and section it, you will find that while the core and jacket will (probably) be properly bonded, the jacket will be noticeably thicker on one side of the core than the other, creating a significant imbalance in flight. The way ultrasound is used in this device does not allow detection of another type of problem that will cause imbalance in flight, a void or bubble in the lead core. It is possible to detect such voids, but the ultrasonic machine that does so is totally different in concept and use and not generally found outside of the inspection departments of large industrial facilities - it's a pricey little devil capable of detecting voids or measuring wall thickness in metallic assemblies, depending on how it's calibrated for the specific job.

Hope the above helps a little.

Mike

Mike has it figured out, the Junke will tell you #1 if the core is seated all the way, it measures if it is compacted 100 %. I use it to check if the cores are seated as i build a bullet it will read center scale if done right. When you point the projo it should read up to 10 points higher on core seating value this insures all bullets are the same. Then you rotate the bullet to see if jacket is good not thick or thin, it should read less than 1 devation unit on the fine scale if so you have a perfect bullet, if it reads up to 5 DU you still have a real good bullet less is a Jewel. To check existing bullets you first check core seating put same #'s in a pile you will have 3 or 4 then roll them for GC take best ones for match rest load work up & fowlers. Hope this helps

 

[Immike]

I was shooting my junk pile that the Juenke said was in a local match, I was 3 shots from finishing what was going to be a new 80 shot range record when they started blowing up in the air.

 

[Preacher]

That machine will even tell you if a case is out of whack.....
I had a 284 case one time that wouldn't ever let a bullet stay in the group, the Junke showed it was off kilter somehow...

 

[Catskinner]

Very interesting I hope this continues . I do remember some one in Virginia was building a machine that looks like the Junke . Does anyone know if this is still in production or if they are still taking orders?

Jim

Jim: I and a friend are becoming a dealer for the new ICC machines, these machines are in Kit form as you have to be Electronic Wizzard to build them. My friend is one we will have i going soon with some updates to the original build. The updates will make the machine easy to use & accurate. AL

 

[amlevin]

Very interesting I hope this continues . I do remember some one in Virginia was building a machine that looks like the Junke . Does anyone know if this is still in production or if they are still taking orders?

Jim

I read some time ago that there was a company building a new version of the Junke. They said their current rate of production was "one per year". That doesn't sound too promising.

 

[Erik Cortina]

Very interesting I hope this continues . I do remember some one in Virginia was building a machine that looks like the Junke . Does anyone know if this is still in production or if they are still taking orders?

Jim

I read some time ago that there was a company building a new version of the Junke. They said their current rate of production was "one per year". That doesn't sound too promising.

It also sounds expensive!

 

[Outrider27]

Here's the last site info I had for an outfit trying to duplicate the original Juenke machine. And it sounds like it will definitely be expensive....

http://www.bulletdoctor.com/BulletDoctor%20Home.htm

Mike

 

[Catskinner]

Very interesting I hope this continues . I do remember some one in Virginia was building a machine that looks like the Junke . Does anyone know if this is still in production or if they are still taking orders?

Jim

I read some time ago that there was a company building a new version of the Junke. They said their current rate of production was "one per year". That doesn't sound too promising.

It also sounds expensive!

Eric: That's the reason you should use my bullets they are all ready spun on the Junke, Fritz is shooting them.

 

[VaniB]

Why do bullets not spin on there center line. Does the point of the bullet wobble when it leaves the muzzle.

https://www.youtube.com/watch?v=uOUqy9G8s6Q

[youtube]http://youtu.be/uOUqy9G8s6Q[/youtube]