2 different readings on concentric tools?

[JGorski]

Had my buddy check the runout on a 6 Creed fireformed from a 22-250 brass and loaded with a 95VLD using a his Sinclair concentric tool, he got .003". I just checked the same round on my new Hornady Concentric tool, I got just shy of .005", of course I corrected it to .002" but what Im wondering is it possible to have 2 different concentric tools to be that far off?
Or is he pulling my leg?

 

[ksthomas]

Re: 2 different readings on concentric tools?

I've seen them a whole lot further off than this. Problem is, it usually comes down to operator error, not a problem with the tool itelf. Play with them sometime and see if you don't get several different measurments off the same tool, measuring the same round, depending on how you manipulate the componets involved. More or less pressure in seating the round in the tool, how much pressure is used when rotating the round, etc.. Very subject to operator error. This is why these tools take both some finesse and experience before you should take the readings as being truly accurate. Take your time and work with it a bit, just learning how to use them properly. It'll pay dividends down the road.

 

[427Cobra]

Re: 2 different readings on concentric tools?

I never trusted the Hornady tool, my technique could have been the problem, but my homemade concentricity tool and its replacement a Sinclair always would read the same, the one I made only did loaded rounds, the Sinclair is easy to adjust and will check loaded, neck, body runout, it is very easy to use, and will help identify where the runout is coming from.

 

[Fuzzball]

Re: 2 different readings on concentric tools?

"Im wondering is it possible to have 2 different concentric tools to be that far off?"

Easily; how the cartridge is supported and where the indicator tip rests can make a world of difference to the gauged number and that varies by the tool's design and user set up. But the number is NOT a precision thing anyway, nor do we need for it to be; it's just a relitive thing. Our goal is "zero" runout and they will all agree at that point.

 

[clmayfield]

Re: 2 different readings on concentric tools?

Fuzzball is right. Distance from neck that you are reading will make a pretty big difference. Also, look at how the case rides in the tool. Which part of the case the roller / support block rides will make a difference. You can set the same tool up a different way and get a different reading. If you want a low number to report on the Internet, you want to set the tool up to give you as low a reading as possible. Otherwise, you want to set your tool up to get as high a reading as possible.

 

[JGorski]

Re: 2 different readings on concentric tools?

I've seen them a whole lot further off than this. Problem is, it usually comes down to operator error, not a problem with the tool itself. Play with them sometime and see if you don't get several different measurements off the same tool, measuring the same round, depending on how you manipulate the components involved. More or less pressure in seating the round in the tool, how much pressure is used when rotating the round, etc.. Very subject to operator error. This is why these tools take both some finesse and experience before you should take the readings as being truly accurate. Take your time and work with it a bit, just learning how to use them properly. It'll pay dividends down the road. [/quote


Using my Hornady tool I can move the dial indicator across the bullet over .100" and still get the same reading, take the bullet off again and again, still get the same reading, compress the spring more on the bullet spindle, change to a slightly bigger hole on the bullet spindle, still get the same reading, so.......

 

[JGorski]

Re: 2 different readings on concentric tools?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Carter Mayfield</div><div class="ubbcode-body">Fuzzball is right. Distance from neck that you are reading will make a pretty big difference. You can set the same tool up a different way and get a different reading. If you want a low number to report on the Internet, you want to set the tool up to give you as low a reading as possible. Otherwise, you want to set your tool up to get as high a reading as possible. </div></div>
He showed me where he set the dial indicator on the bullet so I set my tool/dial indicator up at the same point. I set the tool up according to Hornadys instructions, it's good to go.

 

[Fuzzball]

Re: 2 different readings on concentric tools?

"... you want to set your tool up to get as high a reading as possible."

Ain't THAT the truth, I've read posts of guys who measured 'runout' at the case mouth! That's just a way to measure the roundness of the bullet and kid youself!