I have found that concentricity - how far out of round a bullet is compared to the case - has a significant affect on the accuracy of my loads. I was thinking of getting one of these tools from Hornady and wanted to know if others who had it found it useful.

www.hornady.com/store/...ity-Gauge/

I have a shooting buddy that has one of these and yes, it does work good. Him being a Match shooter from 600 yards to 1000 yards with custom rifles, barrels, and actions can justify the cost.

But for my rifles which shoot 2" - 3" groups at 200 yards, I think I'm doing ok without it and is accurate enough to put meat on the table.

looks like a micrometer, clamped on a case trimmer..
hmm..

I want to get my rifle back to shooting 2" groups at 200 yards. If this helps and saves me one trip to the range, I'm all for it.

I was looking to buy one at the National Matches two years ago to check my 600 yard loads... I ran a box of 50 rounds that I had assembled on my forster Micrometer seater dies and all were under 0.003" with most less than .002". Dave Emary said I will sell it to you.. but you dont need it with that set up... So I left it on the table.

I use one of these to check concentricity of cases and loaded rounds, also use it to monitor case stretching/web thinning and how even the case mouth wall are.
shop.rcbs.com/WebConne...ctId=3180.

the Hornady tool will tell you your concentricity and allow you to do something about it if its excessive, the case master will tell you what's right or wrong but wont allow you to tweak anything.
Hell its only money, buy both.
Having said that I only use it occasionally now to do random checks since I appear to have sorted my concentricity problems out.

I've got one but haven't played with it much yet. Easy to use though. I plan to load 20 rounds, make 10 as concentric as possible and the other 10 "bent", then shoot them at 200 yds to compare groups. Not sure when I'll have time though.

Dawgdad wrote:

I ran a box of 50 rounds that I had assembled ... all were under 0.003" with most less than .002".

Dawgdad, you always seem to have your act together. I would expect nothing less.

dhc4ever wrote:

I use the RCBS tool to check concentricity of cases and loaded rounds,

dhc4ever, I've got a similar tool on loan right now while I'm trying to figure out my concentricity issues. I'm going to use it and compare with the Hornady tool this weekend to see what I learn. The Hornady tool measures concentricity a little different and I want to make sure I understand what its really doing.

Pumpkinslinger wrote:

I've got one but haven't played with it much yet. Easy to use though. I plan to load 20 rounds, make 10 as concentric as possible and the other 10 "bent", then shoot them at 200 yds to compare groups.

I would suggest you need three groups. After you reload, measure the concentricity of all the rounds. Take the ones that are concentric and set them to the side. Then take the ones that are not and divide them in half. Take one half and correct their concentricity. Then when you go to the range, shoot the good ones, shoot the bad ones, and shoot the third to see if the corrected group shoots as good as the ones that didn't need their concentricity corrected.

I may get to this before you. I already shot the group that was concentric and compared to a group that was 0.005 to 0.009 out of round and didn't like the lose in accuracy and velocity I saw.

Two "V" blocks and a bench mounted dial indicator. Works for me.

Bushmaster wrote:

Two "V" blocks and a bench mounted dial indicator. Works for me.

Bushy, I was thinking of making one like this so I have a true measure of concentricity. The neat aspect of the Hornady Concentricity Tool is it has a means to correct a load that is out of round. I plan on stopping at Cabela's on the way home from the airport to check them out. If I pick one up, I will see how well it works tonight.

Bushmaster wrote:

Two "V" blocks and a bench mounted dial indicator. Works for me.

Reel-to-reel's and 8-track's still work for you as well....waszat say??!!

It sayzzz you need to look again.

Three Reel to Reels: Pioneer (2) and a Teac (1)
Two amps. (Front and rear)
Two Cassette decks (Both Pioneer)
One CD Player/Recorder (Tascam)
One Tuner[digital] (Pioneer)
One SQ 4 channel Decoder (Sony)
Eight Speakers (4 Polk Audio R-15 and 4 Polk Audio R-10)
One Turntable (Dual)
A ton of tapes, a tone of records and a ton of CDs

But NO 8 track...

Well this was interesting. I got the last Hornady Concentricity Tool at Cabela's. It looks to be built well except for the set-screw that pushes against the bullet to improve concentricty is pretty small. The Hornady tool measures concentricity along the round's axis using the case rim and tip of the bullet. The v-block uses the side of the case as a reference. I ran 40 rounds through it side-by-side with a v-block concentricity micrometer.

Summary
- In six cases, the Hornady's reading was = to or greater than the v-block. All the others were less than the v-block, in some cases by as much at 0.004 or greater. I think I trust the Hornady because it appears that an irregularity in the side of the brass case can be magnified out at the bullet with the v-block, especially with the short 6.8mm case.
- Only 3 rounds measured greater than 0.003 out by the Hornady. I was able to improve one case from 0.004 to 0.001, 0.004 to 0.002, and 0.005 to 0.004. A couple that were 0.003 out were improved to 0.001 (I was practicing).
- The tool's base flexed noticable when trying to improve runout with the set screw pushing on the bullet.
- I was unable to get any Barnes banded bullets to shift, not even a by 0.001. I think the bands in the bullets grip too much.

That was a lot of work to improve 2 out of 40 rounds. I probably could get better but I don't think I'm going to try.

I know less now than I thought I knew 3 days ago.





I think I know less now.