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Concentricity gauge?!

Jayjay1

Gunny Sergeant
Full Member
Minuteman
Oct 30, 2018
980
499
Who uses one and is willing to share his experiences with us?

I´m thinking about buying me one, but there are some around, so I hope you can help me a bit.

:unsure:
 
What I saw with the Hornady´s is, that it has a correction item, the others seem not to.

Sinclair, RCBS, 21st century, Hornady, Bischoff, .... , are there more?

Any pros and cons?
 
I use Hornady's version. Most of the ammo I check, factory or hand loaded, measures 1-3 thou out but some I've found to be 5-7. Easy correction with Hornady version.
 
I've got an older Sinclair model. Its handy to have to prove out your reloading technique/process if your trying to make accurate ammo.

If you're more inclined to buy ammo and shoot there is good quality ammo available these days.
 
I´m loading my own.

How will I know if I need one or not if I don´t have one?
The shitty, unhelpful, and correct answer is the same as the legal definition of obscenity "you know it when you see it".

A slightly better answer is you might need it if you are encountering ammo problems that can't be checked or explained by other methods. Imagine that your gun shoots factory ammo great, it shoots your friends hand loaded ammo great, yet when you use your friend's recipe with your reloading gear it shoots poorly. So you have a good idea it's not the gun and it's not you.

So you now suspect your gear or process. You next make up a batch of ammo for the friend's gun with a known good recipe and his known good components. And he has the same issue with his groups unexpectedly opening up.

So now you know it's your gear or process. Then pull a few bullets on loaded ammo to see if they are being damaged during seating. Nope, they all look good. At this point you might want to buy the gauge to test concentricity and neck thickness.

Its a great tool but one you are going to use very rarely.
 
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It's one of those items you don't really need unless you like to tinker. I happen to love tinkering and this is what I found.

I was using a value minded set of dies to reload 6.5CM. The general consensus seems to be 0. - .003 TIR for match ammo. I was getting .003-.006 when FL sizing. I upgraded to the Redding FL bushing sizer and micrometer seater and my runout went to .0005-.003. The FL sizer was the fix. Seating with the cheaper die had no discernable effect on runout.

I probably didn't miss any targets due to runout, but I wouldn't have known about it without the gage.
 
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