Do you use them? What is your experience with some brands? I'm looking at the Forster. A shooting buddy lent me his RCBS and I'm sorting through batches of ammo and I was disappointed with TIR of about .005 ~ .01 at the bullet ogive (loaded)

I do.  Mostly to cull out banana shaped necks.   RCBS case master has a rimfire gauge that used to be readily available as an accessory.  It's handy to sort standard velocity .22 to use in a match rifle (match chamber) I have.  Think it would take a little patience to find one now.  Hornady gauge  has an added feature that can reduce bullet run out to a certain extent.  I have rounds ready to test but don't know if it's going to work for me yet.  Feels good to be able to correct run out though.

Don't have a preference for either, far as measuring run out.  Both measured 30 06 GI  match round rounds the same; 1 thou run out.  And my reloads the same; sometimes lots of run out.

I used the Sinclair concentricity gauge to help adjust my dies. My factory rifle didn’t make a diff shooting loaded rounds with .001 run out of .005 run out. In fact I got better groups with the .005 runout.

Maybe it would make a difference in tight chamber custom guns where a few thou would cant the bullet to one side of the bore.

In fact factory rounds which I ran through the gauge were really bad. You can roll the round on a table and see the bullet wobble around. BH, Fed, to name a few. Armscor had better concentricity than BH and Fed.

But would love to hear other peoples experiences with a concentricity gauge and their results.

I'm trying to find out how the Hornady fixes out of round loaded ammo. Can anyone describe how it corrects it?

21st Century and Accuracy One makes some really nice looking setups but it does come with a price to match. Been eyeing up the Redding slant bed setup but so far I haven't been able to find it in stock. Ren, how did you like the RCBS and Ocean 19 how do you like using the Sinclair ?

I'm trying to find out how the Hornady fixes out of round loaded ammo. Can anyone describe how it corrects it?

The hornady holds both ends of the loaded round and a rod pushes/bends the round at a 90 degree angle to "straighten" it.   Neck tension is negatively affected.  Using a factory crimp die afterwards,  is recommended.  Thats how I'm going to test my reloads. 

21st Century and Accuracy One makes some really nice looking setups but it does come with a price to match. Been eyeing up the Redding slant bed setup but so far I haven't been able to find it in stock. Ren, how did you like the RCBS and Ocean 19 how do you like using the Sinclair ?

The RCBS one works but I don't like the vblock setup as there  is some friction and inconsistencies. But it works for spot checking loaded rounds. I have a 3d printed one that uses bearings - I just need to order them from Amazon.

I have been reading the Zediker book about loading match grade .223. He didnt recommend buying a concentrically gauge, he says if you have good gear and set it up properly from the go you wont need one. But his pick if you were going to buy one is a sinclair.

https://www.sinclairintl.com/reloading-equipment/measuring-tools/concentricity-gauges/sinclair-concentricity-gauge-prod37479.aspx

waste of money I.M.O.
Just roll the loaded round on a table and if it is a banana, you got problems.
Spend your money on better components and dies and concentricity will be good.

 I used one on my benchrest loads. Used lapua brass and berger or sierra bullets sorted by weight and bearing surface. Some ammo was less than .001" runout some was closer to .005". I never saw a difference with accuracy between them. If you are like .020 or something like that, you don't need a dial indicator to see it.

I have one but discontinued using it.  Reloading method netted close to zero run out, every round.

1. checked neck thickness on all cases. Anything over .002" variation in thickness gets culled.  uneven wall thickness = banana cases  (Lapua cases hardly get culled, but cheaper brass can be way out.  However, even cheap cases are good to go when measured and found to be consistent. )

2. body size with Redding body die to bump shoulder

3. neck size with Lee collet neck sizer

IMO waste of time. Use good reloading techniques, components and reloading dies. What will you do if you find your rounds have "excessive runout"? I use very similar to Heavies, Lee collet die, Redding body die to bump shoulder, Forster Benchrest seating die. This seating die is really the key. You already know that 100y tells you very little about the load

At 600y, I would put my energy at getting your ES down instead of measuring runout. My $.02

Took some cartidges with runout of more than .005" and shot them. No big difference - shot 1 MOA. settled on 7 shots for a group and called it a test already since components are few and far between.

Took some cartidges with runout of more than .005" and shot them. No big difference - shot 1 MOA. settled on 7 shots for a group and called it a test already since components are few and far between.

1MOA well within the SR 10 ring.