Comments on: Videos Show Functions of Hornady Concentricity Gauge

By: mike

mike — Sun, 15 Jan 2012 00:34:05 +0000

Josh, you might take interest in the first page of this thread:
http://forum.accurateshooter.com/index.php/topic,3767547.0.html

By: Josh Benin

Josh Benin — Sun, 27 Mar 2011 17:50:47 +0000

There’s a lot happening in these videos and the accompanying descriptions. The statement “Run-out is deviation from the cartridge centerline axis.” is probably incorrect as used here since the device is really indicating runout about the axis of rotation. Unless TIR is zero, the axis of rotation is probably NOT the cartridge axis.
The gauge appears to fixture the loaded cartridge on the case head, which is typically screw-machined along with the extractor groove and subsequently nicked and dinged by the rifle’s extractor if previously reloaded. There’s not much reason to expect this to give the same results as fixturing or rotating about the slightly enlarged, fire-formed portion of the case just in front of the web.
It would be nice to see some data and not just folklore. Does “straightened” ammunition perform better than “unstraightened”? Is the difference statistically significant? If ammunition is straightened as shown in the videos, and then remeasured in a different place – say along the case neck – are the results the same?

By: Jr.

Jr. — Sun, 27 Mar 2011 16:56:07 +0000

I’ve used this tool for about a year.If you want to straighten factory rounds,by all means,get it. If you think you can straighten reloads, well not exactly. The important thing is the neck tension and that goes hand in hand with neck wall thickness. Make the bullet release evenly with about .002 or .003 tension.The tool helps me a bunch when I cut cases from another cartridge and have to trim the wall on the neck to exact tolerances.I use inside reamers and outside turners to get the thickness I desire.

By: Benny

Benny — Sun, 27 Mar 2011 00:47:25 +0000

In a singleshot rifle where ammo is put directly into the chamber this would be beneficial but forget it with an autoloader or mag fed rifle unless you dont think the pressure on the bullet to knock it out of concentricity will be greater than the force from the tool itself to make it concentric. . .cycle some ammo real fast through your rifle like in a rapid fire stage without firing it and then check it on the gauge afterwards. . .as beneficial as pissing up a rope. . . Maybe I shouldnt have said anything. “When ignorance is bliss, tis’ folly to be wise”—Thomas Gray

By: mike

mike — Sat, 26 Mar 2011 20:50:57 +0000

RUNOUT & ECCENTRICITY are different animals. Runout is not always w/resp to centerline. However, low TIR generally indicates that ammo is both straight, and concentric.
Sinclair’s V-Block(only with bearings)is actually a runout gauge, and not a concentricity gauge.
That’s why readings are different between them.

By: Taildrag15X

Taildrag15X — Sat, 26 Mar 2011 13:03:49 +0000

A fancy Hornady take on the Bersin Tool…..must be the Patent ran out.

By: Jack N eale

Jack N eale — Sat, 26 Mar 2011 03:41:46 +0000

I have been using this tool since last year, and I love it. After many groups shot, I can say that it does improve the accuracy of my handloads.