Internal Concentricity Comparators

[mdesign]

Anyone have experience with one of these or with bullets sorted by the one? Interesting article...seems like it could have some advantage to the long range shooter if it worked as advertized.
Verne Juenke's Internal Concentricity Comparators

 

[ChrisGarrett]

Re: Internal Concentricity Comparators

I got a Bersin concentricity gage for my 7 RemMag and plan on picking up the 223/308 body which will accept the .0004" dial indicator I use with it.

This corrects runnout after the fact and is quite easy to use, with twice the resolution of typical runnout 'indicators'.

From my research on the net, runnout is mostly caused by case walls of varying thicknesses, expanding and contracting at different rates, causing the case to take on a 'banana shape'.

The Bersin gage allows me to bend that case back at the neck and achieve alignment with the bore.

Chris

 

[Victor N TN]

Re: Internal Concentricity Comparators

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: mdesign</div><div class="ubbcode-body">Anyone have experience with one of these or with bullets sorted by the one? Interesting article...seems like it could have some advantage to the long range shooter if it worked as advertized.
Verne Juenke's Internal Concentricity Comparators </div></div>

I used a Verne Juenke machine when we were making benchrest bullets. It uses ultra sonic waves to find the differences between different metals. It DOES NOT read in thousandths or tenths. It reads in seperate increment numbers.

If you have a need for such an instrument, there is nothing else like it. If you only want a few checked I'll do it if you aren't in a hurry. If you have to have it tomorrow and ship it Fed Ex, you're on your own.

In my own experiences I can rate MOST bullets out of the box.

The worst are the home made Corbins I've tested with jackets made from 22lr cases.
Sierra is next to last. Some Sierra bullets can't even stay on the sweep dial of the meter.
Speer bullets are OK for banging steel. But some are very good.
Winchester and Remington bullets are middle of the stream.
Nosler Ballistic tip or the Combined Technology are better than most on the market.
Hornady is very good quality.
Berger bullets and any custom hand made bullets that use J4 Jackets are as good as it gets for jacket uniformity. But boosting them over 3000 fps is rough on their thin jackets. If you're running their regular jackets over 3000 fps expect a few to not make it to the target.
The Lapua Scenars I inspected are in the same range with the Bergers. At that, I prefer to buy Made in the USA when I can.

If you have other questions I didn't answer, just email me. I'll do my best to answer you.

 

[mdesign]

Re: Internal Concentricity Comparators

Thanks Vic

In the article I posted the link to, the author was basically saying that brass sorting/prep did not matter as much as bullet quality and performed a side-by-side test with good/bad brass to prove it.

...here's my question,

Do you know if one used this machine to sort bullets and separated good/bad bullets, would the "good" bullets consistently out perform the "bad" ones? Assuming all other things were equal. Have there been any data or articles like this published?

 

[Victor N TN]

Re: Internal Concentricity Comparators

The machine I have is about 10 years old. It will adjust to run either brass cases or bullets / jackets. I use it primarily to check the internal concentricity of finished projectiles.

If you are talking about a quality rifle capable of consistantly shooting groups... say .125" or 1/8" at 100 yards. Yes you can tell the difference if you shoot 10 groups and measure center to center. Then shoot the ones with the run out. The difference will be more noticable at 300 yards. But if you have the basic quality needed to see the difference, yes you can tell.

If you are banging steel at 100 to 300 yards or shooting a hunting grade rifle, maybe you will and maybe you won't see the difference.

Basically when I was doing all the inspection what you see over time is the inside of the bullet if exagerated would show up slightly egg shaped. That's the brand you want to stay away from. Thick and thin places in the jackets when they are drawn in the pressing operations is what the Verne Juenke machine detects. These differences are sometimes less than one tenth of a thousandth 0.0001" But when you are spinning it at 180,000 rpm and throwing it downrange at 3,000fps even the smallest variations can make a big difference if you and your equipment are up to the test.

I have notebooks full of data. But I'm not going to publish the brand names. But there have been several people on here that I have inspected bullets for. Maybe someone else will speak up on the process.