Preferences regarding Concentricity Gauges

[Petros284]

Whatever you decide be sure to get one with a "Jeweled" style indicator and the optional wheel such as the 21st Century (which reads in .0005 increments). Much more precise and accurate!

 

[quest450]

where exactly do you measure the runout of a loaded round, ogive line ?

 

[Petros284]

where exactly do you measure the runout of a loaded round, ogive line ?

That is what we recommend

 

[Hotrod6.5]

the Accuracy One for me.
I started with the H&H and consider it junk in comparison. I put a good Mitutoyo jeweled indicator on my AO and love it.
I know some say checking concentricity is not necessary but i do it for several reasons.

I probably use it more to verify straight necks that are running true to the bodies than i do for bullet seating. You can discover a lot about your sizing operation by spinning the brass and indicating the necks. when i saw how much run out i was getting from my bushing dies i understood why my bullets were running out like they were. I made a call to Al Warner and ordered one of his big seizing dies and custom inserts for the calibers i load for and never looked back. Best money i have ever spent. Once the case is perfectly straight it is much easier to get near zero run-out on a seated bullet at the ogive. I rarely use the indicator once i start seating bullets because they just don't run more than a .001 at most. The Warner die also produces the same "zero run out" results with .003 and more neck tensions.
I use my Accuracy One to check the effect of bullet run out with increased neck tensions for guns and powders that like more grip on the bullets. when i find a bullet with maybe .004 i can push down the high side and normally they go back very close to zero. I think this is due to the pressure ring on our bullets causing a gimbal effect on bullets seated with tight neck tensions. I know i probably go way too far down the rabbit hole but it makes me happy when i know i have made the most accurate ammunition I can.

 

[charlieyankeesierra]

I have an Accuracy One. I prefer the H&H for focusing on bullet runout. I like the Accuracy One for examining the case neck.

 

[varget204]

I use a Sinclair concentricity tool,and a Hornady,Once in a while i'll get a round off .00175-.0025,i use the Hornady to Lower to .001.Have seen people with .003 to .005 TIR,that were cutting groups in HALF,using Hornady Tool.Groups went from 1-1 1/4 " to 1/2" to 3/4".I think it works the best w/ shells that are within .002-.004 off.Also on Factory Rounds that are not concentric.I use the Sinclair to check cases,if i get one .0015 or more off, I toss it.I've bought Expensive Redding Competition Neck dies that resized cases .00015 to .002 OFF,without the Sinclair would never have Known die was Off.

 

[Richard Coody]

21st century makes a good one.

You need to be pretty far down the rabbit hole to benefit from it.

Really will teach you a lot about sizing and seating dies and your press setup. After you master that for most the concentricity gauge will mostly gather dust.

Same with the force gauges on an arbor press. They will teach you tons about brass prep and consistent neck tension. Once you have mastered that then you can teach the class

 

[marchboom]

I have had a Sinclair concentricity gauge for a number of years and it works great. But due to pressure from the dial indicator plunger on the case neck the base end of the case would flip up and had to be firmly held down. This resulted in a somewhat jerky reading. This was while using my best Starrett dial indicator. I decided that a test indicator would provide less downward pressure and, therefore, result in a smoother reading.

The test indicator "style" concentricity gauges are rather pricey so I gathered up the parts I had and made my own. The magnetic base has an "on-off" switch which allows for easy movement on the steel plate. The knob on the rod that holds the test indicator allows you to lower the indicator's arm onto the case with very little pressure. A much more accurate reading is the result.

 

[South Pender]

I have had a Sinclair concentricity gauge for a number of years and it works great. But due to pressure from the dial indicator plunger on the case neck the base end of the case would flip up and had to be firmly held down. This resulted in a somewhat jerky reading. This was while using my best Starrett dial indicator. I decided that a test indicator would provide less downward pressure and, therefore, result in a smoother reading.

That's exactly the problem I've had with my Sinclair gauge and is the reason for my inquiries into what others have found. The Hornady model looks pretty good to me and not as stratospherically expensive as the AccuracyOne and some others.

 

[South Pender]

I wouldn't waste your time worrying about runout gauges. Runout is a bi-product of a good brass prep process not a goal. I have the Accuracy 1 gauge, which is the gold standard, but I seldom use these days. If you do the other stuff low runout is the natural result like 2 + 2 = 4.

I made this video just for you.

Thanks, Joe. That's a great video; I really enjoyed it. You've obviously taken the process much further into the weeds than where I am at present. The idea of establishing neck tension via a mandrel in a die after resizing is interesting. I think you'd need a selection of mandrels for each caliber, and being able to get into the 10-thousandths (which I would think would be necessary) would appear to be pretty expensive given the cost of the pin gauges.

My only reason for wanting a good concentricity gauge is to get an accurate picture of the precision of the various steps of my handloading practices. I agree that, once you've mastered the various steps, there's little need to continue to assess runout.

 

[Richard Coody]

Stay away from the Hornady runout gauge, its a waste of money. Can't say you weren't warned.

By the way, this the only correct way to measure brass runout. You could do it on the bullet bearing surface, but the runout could also be introduced by your seating die. Measuring runout on the outside of the case neck is analogous to examining the outside of the barrel to see how straight the bore is.

Kindest regards,

Joe

View attachment 1098243

I agree the hornady is not a good tool and the idea that you can straighten a crooked round is ludicrous. What would that do to neck tension.

As to measuring runout on sized brass on this inside. That kind of.depends on whether you use a sizing die with a bushing or an expander ball or mandrel. If your brass neck thickness varies at different points as much as 0.0015 to 0.002 that will show up as concentricity. If you use a bushing the the outside measurement won't pick up the difference in brass thickness. It will show on the inside. Vice versa on the expander ball. That is why turning necks is an important part of brass prep. That is if you really want to go down that rabbit hole. That is also one of the reasons that many find that a conventional full length sizing die with expander often makes straighter rounds than a bushing die.

 

[Richard Coody]

Really?

Of the guys I shoot F-Class with in Houston, I literally don't know anyone that uses an expander ball.

Just think about it, the idea of pulling an expander ball through a neck and not disturbing the geometry of the neck and shoulder makes about as much sense as a baby going through a vaginal canal without pain.

Joe

Whatever works for you. Lots of ways to skin this cat.

Might check out John Whidden's website. He has a video the explains the difference between bushing and non-bushing dies and even states in the video that they find less runout with the non-bushing dies. He also sells an expander ball kit that allows you to adjust neck tension just as you would with bushings.

People are sucessful with all sorts of reloading techniques. There is no right or wrong way. Only the way that works for you

 

[dblizzard]

I moved up to a NECO from a Hornady. A concentricity gauge is needed to establish the fact that you do have quality seating dies & spot checking for run out also assures you are using them correctly. I have also found NECO useful for measuring case wall thickness variations. My Hornady run out gauge is for sale.