The best concentricity gauge

[Hoser]

I dont know about best, but my Accuracy One is the easiest to use of any I have tried.

 

[Mulligan]

I think a quality concentricity gauge is not just a useless tool to check runout of your loaded round, I check concentricity of sized case and with a nifty little attachment I can check neck wall thickness variation after neck turning, it's another tool I can verify that my reloads are uniform and consistent eliminating outliers and variations, the OP asked for "best" yet few posters are trying to justify the $$$ they spent on low quality tools that collect dust......garbage in garbage out.

^^^^THIS^^^^^^^

My concentricity gauge gets plenty of use.
I’m not sure why folks think otherwise?
CW

 

[Mulligan]

The Sinclair is a good one. It's simple and repeatable. The Redding slant bed indicator is another one I can recommend.

While the value of concentricity is something each person has to answer for themselves (trust the target ), the value of a good concentricity guage  really lies in being able to qualify dies, neck bushings and individual steps in the loading process.

Good shootin' -Al

Al, you nailed it.

Check concentricity on your cases prior to and again after case trimming. I have and I discovered a lot! Bushings, collets, collars, whatever…. Check how it fits into YOUR system.
CW

 

[Benchrest Braxton]

Yep. Neck bushings can be a real eye opener.

@Flea21 and I just dealt with the same thing a few weeks back. Short action customs bushings fixed that.

 

[Flea21]

@Flea21 and I just dealt with the same thing a few weeks back. Short action customs bushings fixed that.

Yessir, This is true. I got SAC bushings and immediately everything changed. TIR was .0005 or .000… occasionally I’d get one that was .001 but the average was .0005

Get one and see for yourself.

 

[bobm]

Did someone mention the best concentricity gage?

 

[ELR LVR]

I use this one, works fine, rollers would be kind of nice but, it measures well. Is Solid, doesn't flex etc.
maybe rollers are just another part to worry about, upkeep, wear out. While V-blocks are always on point

 

[gero]

Yessir, This is true. I got SAC bushings and immediately everything changed. TIR was .0005 or .000… occasionally I’d get one that was .001 but the average was .0005

Get one and see for yourself.

.......get rid of your expander balls, use sac die with bushing and mandrel, never look back....

 

[searcher]

I use this one, works fine, rollers would be kind of nice but, it measures well. Is Solid, doesn't flex etc.
maybe rollers are just another part to worry about, upkeep, wear out. While V-blocks are always on point

I believe that is the RCBS, as I used to have one of those. The little black arm with the claw tip can be taken out and makes the best device for running inside your cases to detect impending case separations. It works better than anything I have tried that was made to do that job.

Regarding the unit itself, I thought it was pretty good till I bought the Sinclaire unit with the bearings and built much "beefier". I gave my RCBS unit to a buddy but should have kept it just for that little black arm....

 

[Flea21]

.......get rid of your expander balls, use sac die with bushing and mandrel, never look back....

I dont use expander balls. I go back and forth between bushing only and expanding mandrel. Have had great success with both, and if i can get away with an extra step in the reloading process with no noticeable difference on target... then so be it.

 

[Benchrest Braxton]

I dont use expander balls. I go back and forth between bushing only and expanding mandrel. Have had great success with both, and if i can get away with an extra step in the reloading process with no noticeable difference on target... then so be it.

i think he was saying more in general, not directed towards you.

 

[Flea21]

i think he was saying more in general, not directed towards you.

Oh Okay, i though he was saying towards me.. my bad. We're both doing the same thing a little different striving to get to the best end result... no offense taken.

 

[ELR LVR]

I believe that is the RCBS, as I used to have one of those. The little black arm with the claw tip can be taken out and makes the best device for running inside your cases to detect impending case separations. It works better than anything I have tried that was made to do that job.

Regarding the unit itself, I thought it was pretty good till I bought the Sinclaire unit with the bearings and built much "beefier". I gave my RCBS unit to a buddy but should have kept it just for that little black arm....

:O YESSSS, I had not thought of using that little pokey arm for that
I have a paper clip bent in an "L" with the end flattened out that I used to feel for head seperation
Thanks for the tip, I'm going to try this!!!
I thought that little black arm was for measuring 22 rimfire case heads or some such thing.
(Like I measure 22 rimfire ammo LOL)
---
BTW I use this thing CONSTANTLY - it has held up well for thousands of rounds
it adjusts quickly going from things like a long .284 case to a short 22BR
The V blocks have gotten smoother over the years

 

[Benchrest Braxton]

:O YESSSS, I had not thought of using that little pokey arm for that
I have a paper clip bent in an "L" with the end flattened out that I used to feel for head seperation
Thanks for the tip, I'm going to try this!!!
I thought that little black arm was for measuring 22 rimfire case heads or some such thing.
(Like I measure 22 rimfire ammo LOL)
---
BTW I use this thing CONSTANTLY - it has held up well for thousands of rounds
it adjusts quickly going from things like a long .284 case to a short 22BR
The V blocks have gotten smoother over the years

this is what you need

https://www.amazon.com/dp/B000BKYRM6/?tag=accuratescom-20

 

[ELR LVR]

I bought one of these for a buddy just starting out
He had already bought some of my reloading stuff to get into Long Range and accuracy reloading
I sold him a Nice Rockchucker, a tuned RCBS Scale etc etc
and knew he didn't want to keep soaking tons of money into additional items just yet
One thing I emphasized to him was Don't skimp on your Dial Calipers
Skimp on this instead if you wanna, make one from V-blocks,
roll them across your table and use your eye if you have to
---(I can see .010" deviation easy with just a naked eye)
So if you can't see any wobble you're probably good enough (within .003")
But forget those cheap $30 calipers
This is a 3D printed job from Ebay
Works well for a mere $50 but is mostly plastic
You have to supply your own gauge
I believe it can use a Depth or test type indicator - I used a Depth type like pictured here

 

[ELR LVR]

I dont know about best, but my Accuracy One is the easiest to use of any I have tried.

I use mine to measure Bullet runout on a loaded round----
----Ummm, what are you doing?
----And what are you gonna do if you measure any runout there

 

[Benchrest Braxton]

I use mine to measure Bullet runout on a loaded round----
----Ummm, what are you doing?
----And what are you gonna do if you measure any runout there

measuring case runout? you never heard of that before?

adjust die, change bushing, change dies, etc.....

 

[ELR LVR]

measuring case runout? you never heard of that before?

adjust die, change bushing, change dies, etc.....

Yeahhh
I heard of it
Never experienced it other than with new cases which hadn't been fireformed yet though
Which is why I wondered, what the heck do you do if you have case runout there
Put a rod in the neck and try and bend it back straight like an aluminum arrow?
Lol
maybe My dies are decent then huh? (Mostly Redding, some RCBS)
My RCBS gives .003" or less bullet runout with their standard .308 dies for example
There's a few things I read of guys having issues with that I hadn't run across myself
and thats over 30 years of reloading and 18 different calibers
My Redding Dies usually give me .001" or less Bullet runout
So I also do not see the need for an arbor type press when other guys complain of bullet runout if you dont use one of those
--------------------
So you can understand, with the bullet sticking way out there
and if I only get .003" or less near the middle of the ogive
How little I would read at the neck of a case.

 

[Benchrest Braxton]

Yeahhh
I heard of it
Never experienced it other than with new cases which hadn't been fireformed yet though
Which is why I wondered, what the heck do you do if you have case runout there
Put a rod in the neck and try and bend it back straight like an aluminum arrow?
Lol
maybe My dies are decent then huh? (Mostly Redding, some RCBS)
My RCBS gives .003" or less bullet runout with their standard .308 dies for example
There's a few things I read of guys having issues with that I hadn't run across myself
and thats over 30 years of reloading and 18 different calibers
--------------------
So you can understand, with the bullet sticking way out there
and if I only get .003" or less near the middle of the ogive
How little I would read at the neck of a case.

again, maybe its a user issue, set up issue, die issue, bushing issue, etc. it can be resolved

 

[Timon]

Whenever I feel that I want to check runout, I buy a Sinclair one on this site for $75-$90. After I test what I want, I generally sell it again. The only time I have used one is when I go to a full new setup. I use very good dies, so I really don’t worry about it that much. I think for the most part, they just sit on people’s shelves.