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concentricity tools

06 Jul 2015
@ 09:39 pm (GMT)

Ben Law

can anyone recommend a good tool that can be bought in oz for checking case neck and bullet run-out?

the hornady tool seems the most common here, but I think a simpler v block design would be preferable.

Replies

07 Jul 2015
@ 05:21 am (GMT)

Jon Short

Re: concentricity tools
I use a Sinclair Concentricity Gauge on Nathan's recommendation. The case sits on top of two pairs of ball bearings for support & is simple & accurate. Really happy with it.

I ordered the unit from the states. here's the link to a Youtube promotional clip;

https://www.youtube.com/watch?v=HTkjkhKoE9U

I looked at the design of the Hornaday unit & thought it was poor. I could see how it could give you errors & be miss leading as it relies on the base of the case being true from memory... not the smartest design in my view.

Cheers,

Jon

07 Jul 2015
@ 05:28 am (GMT)

chris murphy

Re: concentricity tools
Hi Ben have you thought of making one. have a look at http://www.ballisticstudies.com/Resources/Discussion+Forums/x_forum/18/thread/4476.html
07 Jul 2015
@ 08:13 am (GMT)

Ben Law

Re: concentricity tools
Quote:
I use a Sinclair Concentricity Gauge on Nathan's recommendation. The case sits on top of two pairs of ball bearings for support & is simple & accurate. Really happy with it.

I ordered the unit from the states. here's the link to a Youtube promotional clip;

https://www.youtube.com/watch?v=HTkjkhKoE9U

I looked at the design of the Hornaday unit & thought it was poor. I could see how it could give you errors & be miss leading as it relies on the base of the case being true from memory... not the smartest design in my view.

Cheers,

Jon



jon, i had similar thoughts about the hornady. the sinclair looks nice and simple, i was hoping to avoid buying from o.s.

Quote:
Hi Ben have you thought of making one. have a look at http://www.ballisticstudies.com/Resources/Discussion+Forums/x_forum/18/thread/4476.html


funnily enough chris, yes i have, as i already have a dial gauge.
i was thinking a v block or marbles used in similar fashion to yours.
i like your design, simple and the steel is perfect for the magnetic base.

how have you found yours?
i think ill give it a go, if its not much chop it wont have cost me much.
07 Jul 2015
@ 08:18 pm (GMT)

chris murphy

Re: concentricity tools
Ive found mine to be great works a treat. I tested it on the tail stop from my lathe and it showed less than .01mm run out so figured it must work
07 Jul 2015
@ 08:36 pm (GMT)

Jon Short

Re: concentricity tools
Hi Chris,

Yeah the Hornady tool may be accurately made, but t's the case base that may not be square or true you see, which could give you a false reading at the neck end. That is my concern with the Hornady system. eg the Hornady system assumes the case base is square/true/at 90 degrees to the case centre line which it may not necessarily be.

Not sure how much of an issue that could be as I have not used one.
I just prefer to be checking concentricity about the case body for geometry reasons & lesser risk of errors.

Cheers,

Jon
19 Jul 2015
@ 05:03 am (GMT)

Ben Law

Re: concentricity tools
well i knocked up the jig the other day.
cost me about $15 for the dome nuts and some threaded rod, as i already had the dial gauge and magnetic base.
works well.

[/img]http://i44.photobucket.com/albums/f3/bjwlsdmf/P1010731%20-%20Copy_zpszl0bvfth.jpghttp://i44.photobucket.com/albums/f3/bjwlsdmf/P1010730%20-%20Copy_zpsdsmzx5jr.jpg[img]

i can see all my fire formed brass has .001" or less runout.

my 223 handloads are mostly the same but a few had upto .005" bullet runout, i suspect this is from occasionally not quite sitting the bullets square into the neck when seating (seems easy to do with the little 223) (the bigger rounds are easier to sit the bullet straight and are pushed further into the neck which i think helps pull them back into alignment)

i have some 30-06 once fired donor brass which i have full length sized that measured .003-.009" runout, tried running it through the lee collet die but that only improved it by .001-.002 at best.
the same batch of brass that i used for some load testing has .001" or less runout so i after fire forming the brass should be all good.
after seating bullets i will try bumping them with the old block of timber with a hole drilled in it, see if that gives an improvement.
19 Jul 2015
@ 05:05 am (GMT)

Ben Law

Re: concentricity tools
[/img]http://i44.photobucket.com/albums/f3/bjwlsdmf/P1010730%20-%20Copy_zpsdsmzx5jr.jpghttp://i44.photobucket.com/albums/f3/bjwlsdmf/P1010731%20-%20Copy_zpszl0bvfth.jpg[img]
19 Jul 2015
@ 05:09 am (GMT)

Ben Law

Re: concentricity tools



01 Aug 2015
@ 10:55 pm (GMT)

Ben Grady

Re: concentricity tools
Quote:
Ive found mine to be great works a treat. I tested it on the tail stop from my lathe and it showed less than .01mm run out so figured it must work


Hey Chris.

Thanks for helping me build a concentricity gauge, all the parts have been ordered and were on sale which is a bonus. I cant remember what yours looked like when you checked my loaded rounds? Any chance of adding a picture. Is it the same as Ben Laws one?. Is the base just a square steel tubing? and how do you attach the dome nuts? with counter sunk bolts?
02 Aug 2015
@ 01:46 am (GMT)

Ben Law

Re: concentricity tools
I drilled and tapped holes into the 50x50x5mm shs and cut short sections of threaded rod and screwed them in.


It can be interesting when you discover some really poor ammo.

I have some factory stuff that doesn't shoot too well, one round measured .017 run out at the projectile.

I'm interested to see if/how much accuracy improves once all my brass is fire formed and neck sized compared to my fl sized rounds that have poor concentricity.
02 Aug 2015
@ 02:17 am (GMT)

Chris Murphy

Re: concentricity tools
hi Ben yep mine is basically the same as Ben's one pictured
02 Aug 2015
@ 03:27 am (GMT)

Ben Grady

Re: concentricity tools
Thanks Ben and Chris.
What tolerances do you guys keep to, for the projectile and case?
Mine will be in mm.

When Chris checked my loads he said the projectiles were just inside the acceptable tolerance (can't remember what it was?), but if I turn the case 180 degrees while seating I may improve on that. So I will be interested to see if there is an improvement.
02 Aug 2015
@ 08:47 am (GMT)

Ben Law

Re: concentricity tools
i'd be aiming for .001" or less. upto .003" might still work alright.

.001" = 0.0254mm.
02 Aug 2015
@ 06:52 pm (GMT)

Chris Murphy

Re: concentricity tools
By memory in the reloading bible Nathan said .003" is max (.0762mm) I keep mine to .03mm for long range or am happy with .05 out to 500yard sort of rifles
23 Aug 2015
@ 12:08 am (GMT)

Shawn Bevins

Re: concentricity tools
[/img]http://img.photobucket.com/albums/v693/shamus1/hunt/IMAG1006-1_zps98989c04.jpg[/img]

Here is the one I made. It works and it was cheap. I borrowed and used an RCBS and a Hornady. Wrote a previous post on what I thought of them.
27 Aug 2015
@ 08:22 am (GMT)

Ben Grady

Re: concentricity tools
Here's mine. Seems to work well. Cost $110.00

27 Aug 2015
@ 09:24 am (GMT)

Warwick Marflitt

Re: concentricity tools
Brilliant Ben. Nice and simple and it works.
29 Aug 2015
@ 06:18 am (GMT)

Ben Grady

Re: concentricity tools
Thanks Warwick

My rounds seem to be within one of the increments, so .01mm. and .02mm at the worst. So my dies must be o.k. I also turned the bullets 180 degrees while seating them and this has helped. Just need to get back to the range to sort my seating depth.
29 Aug 2015
@ 09:48 am (GMT)

Warwick Marflitt

Re: concentricity tools
Lol I tested my run off by shooting at some deer. They must be good? None of the deer ran off so I guess that there's no run off in my reloads! Haha!
31 Aug 2015
@ 04:55 am (GMT)

Ben Law

Re: concentricity tools
just thought id post an update, fired a few test rounds on the weekend with quite an improvement.

after attempting to bend the rounds back into decent concentricity i managed to get most of them back to around .003", some better and a couple a bit worse.

i wasn't really expecting too much, first time groups were between 2.5-4" and this time 1"-2" with most close to 1" so i was pretty happy with that, i should be able to improve on that with another couple more load develpoment sessions.
04 Sep 2015
@ 07:48 pm (GMT)

Ben Grady

Re: concentricity tools
Hey Ben

Thanks for the data. I take it that's all you changed in the process and groups improved heaps. There are so many intricacies that effect accuracy it's mind boggling. Why I ever became interested in reloading beats me, I'm starting to wonder if it was a good idea :-) (or maybe that's why I love it)
04 Sep 2015
@ 10:42 pm (GMT)

Ben Law

Re: concentricity tools
first time i tested 50gr - 52.5gr charge weights.
second time was 47.5gr - 49.5gr.
i will be retesting 50gr - 52.5gr loads soon.

first time i think there were 3 groups @ 2.5" and 3 groups @ 4"
next time 3 groups @ 1", 1 @ 1.5" and 1 @ 2".

that is all that was changed.
07 Sep 2015
@ 06:57 am (GMT)

Ben Grady

Re: concentricity tools
I checked the ammo I had in the safe and most was looking good. 25-06 .01-.02mm. The worst reloads were some for my 25-303 .05mm run out. Then I tried some old CAC .303 ammo, solids with the bullet nose drilled out. These had a run out of .20mm
 

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