Thoughts or Experience With This Concentricity Gauge

[searcher]

With that design, the rollers have to be perfect to not ad to the runout reading. The first thing I would do if I bought the one is spin a ground rod t make sure the rollers were round and the holes in them centered. The non rollers designs are fool proof.

It is pretty amazing the runout on a typical bearing. I doubt the Chinese bearings would be any better.... Even in the precision lathes, companies tend to use a certain brand of Japanese bearings known for their low runout. Everything gets telegraphed - as you noted!

 

[jpjulian]

If you are going to buy a concentricity gauge, buy the Sinclair gauge. Far less complicated than the one you pictured. As others have said, and I had to find out for myself one time, it really doesn't matter on target. Again, as others have said, It can help setting up your sizing dies. I do have to give props to my wife of 49 years as it was she who gave me said Sinclair gauge as a Christmas gift, so don't ask to buy mine.

 

[6BRA]

A thought, if you chamber a round with a TIR of .007, basically twist the bullet into the chamber. Wouldn't this apply an unequal force to the case neck on 1 side? I know there are those that have said no difference on target. Neck tension/ bullet release matter? I used my concentricity guage to define what reloading process needed pitched. Once I figured out how to obtain consistent .0005 runout on the neck, the guage has been sitting.

 

[Bill Norris]

A thought, if you chamber a round with a TIR of .007, basically twist the bullet into the chamber. Wouldn't this apply an unequal force to the case neck on 1 side? I know there are those that have said no difference on target. Neck tension/ bullet release matter? I used my concentricity guage to define what reloading process needed pitched. Once I figured out how to obtain consistent .0005 runout on the neck, the guage has been sitting.

It seems as if that unequal force gets lost in all the other noise. IMO applying pressure to the case neck outside surface area does not actually mean that pressure would be felt by the bullet at launch.

 

[Lucky Shooter]

The rail gun post has taken some of the sting out of this. Building your
loading process to produce .004" runout sounds a lot better than the
constant struggle to get it down to zero.

Where on the bullet is the practical place to measure ?

Most of my runout occurs during bullet seating with Redding Comp Dies.

Boyd Allen has put me on a method to reduce seater induced runout
by reducing the length of the sliding sleeve-----not tried yet.

I think I'm in love with the idea of a simple .003" method.

A. Weldy

 

[BoydAllen]

IMO the main ingredient for straight ammon is straight cases. If we are talking about benchrest and tight necked chambers, there are two principle ways of accomplishing this, a custom one piece die with a die neck ID that gives the desired neck tension right out of the die. With one of these (actually not custom but factory with luck on the dimension) I have consistently gotten end of neck runout of under .0005 sizing turned PPC cases for a .263 neck chamber. The other way is based on a more recent development, the Short Action Custom sizing bushings, the ones that fit where Wilson type bushings do. They have a different design where the neck enters the bushing, that centers it on the case neck and results in a lot straighter brass than I have seen from any other bushing. There are several credible reviews on You Tube. The one thing that I would mention is that the spring back that they produce is different by about a thousandth. A friend has to use one that is .255 to get a .256 neck OD. One of the reviewers found this was not due to the bushing ID being to spec'. He started out with a SAC bushing that pin gauged at the marked ID and compared it to a standard bushing that pin gauged to the same ID. The result was that in order to get the neck OD he wanted, he had to order a SAC bushing that was .001 smaller. One other thing, they are spendy. By the time I have one in hand, I am out about $50, but that is a lot cheaper than a custom one piece die, and since about 20% or that was shipping, ordering multiple bushings would be more economical. I suggest that you determine your neck tension and case neck OD using conventional bushings and then based on those results, order one or more SAC bushings, assuming you have chosen to try to minimize end of neck runout.

 

[Fuj]

You should save your money and buy Alka Selzer instead.

I prefer Rye......

 

[Fuj]

That was on believe the target interview. Fclass john also did a video where he deliberately cocks the bullet sideway enough it is clearly visible on video. It didn't really make much difference on target.

Barrels with real long throats solve most run out problems. I would
add that anyone shooting a tight chamber, zero free bore would want
to check run out for peace of mind......For what it's worth.....Some time
back, I picked up a Lee Dead Length Seater for my 250/3000. It has a
.105" free bore. Best $15 bucks I spent for this particular rifle. They come
out straight and the woodchucks can't tell the difference.

 

[Murray Brook]

Always felt the the Lee dead length bullet seater is the best seater die that comes in a standard die set. Add on the new Lee micrometer top and it gets even better. I have one of these and they are very accurate and easy to read markings along with being very well priced. JMO