Home Forums Reloading Big Game Rifles Concentricity and Runout Tools

What are some of your favorite tools for measuring runout, neck concentricity and thickness, etc? Are the mult-function tools like the forster or rcbs the way to go?

I like the Forster's ability to measure neck thickness, etc, but for strictly measuring concentricity, the Sinclair tool is easier and quicker to use. If forced to use one tool to measure it all, I do like the Forster.

Am using the Hornady and it gets me in the .001 to .0015 range or less. Good enough for my long range shooting...at this point in time.

I purchased the hornady concentricity gauge last summer. Extremely easy to use and easy to fix any runout you come across.

I splurged and purchased the AccuracyOne concentricity gauge and absolutely love it.

A word of advice, don't hangout at 6mmbr.com or you'll end up buying stuff like that.

I've just stuck with the RCBS gauge, works fine for me.

You do realize what a slippery slope this is?

LOL. If you're already thinking about concentricity and such, you're already going downhill at 60 mph.



I have an RCBS Casemaster in the classifieds if anyone's looking for such.

Truth has been spoken.

When you guys measure runout do you count the total sweep of the dial total indicated runout or divide that measurement by 2 ?

Total indicated runout (TIR)

Both. Total Indicated Runout is what is usually referred to. But with the Bersin tool in particular and maybe others you end up centering your indicator to sweep equally between the positive and negative runouts. On the negative runouts you use the Bersin tool to gently push the bullets back in line. You can go from say -.007 sweeps either way for .014 total runout down to .001 sweeps either way for .002 total runout. Sounds more complex than it really is...............dj

I think I've reached the platue on my concentricity endeavors. I've recently started neck turning and have switched to FL bushing dies on my most commonly loaded cartridges. I am still leaving the expander ball in the bushing dies and it is just slightly dragging on the neck on the upstroke. Majority of my loaded rounds are .002 or less with boat tail bullets. And flat base are averaging. 003 or less. I do occasionally still get a few .004 or higher but I've probably reached the good enough point for my needs. I'll experiment a little with the expander ball removed from the bushing die to see if i get any improvement but its making such light contact as it is I'm doubting I'll see much difference.

Remove the expander ball! All it's doing is pushing out the necksizing you just did! The expander ball is the most common culprit in inducing runout when sizing brass........

I know this is heresy but at what point does it matter? Up to .002 doesn't make much difference in my hunting rifles with my shooting. Then one military study showed that greater than .006 and the chamber more or less straightened out the round when clambering. I am lusting after the 21st Century model but question if I need it that much. Using a home made one now. Where it would be helpful is verifying that I have set up the dies properly but I usually do this just once and then have either double lock rings or where appropriate an O Ring to float the die so one time deal for each rifle.