Concentricity tool



  • What are you using, and why are you using it?



  • I don't have one at this time, I used to borrow one from one of my good friends when I lived on the same island as he did.
    He had one of these:

    99% of the Lawyers make the rest look bad.

    1


  • Don't get a hornady. mine has about .003 slop in it. makes it really hard to tell if the round is really concentric or not.

    I bought the concentricity tool before I had a good press and dies. In my limited experience you don't need a concentricity tool when you have a good press and dies. I haven't used it at all in a few years now.



  • I use the Sinclair guage. It's very good from my experience, but I have not used any other brands.



  • 76251dac9d3c8202ecd296848a63060e_c5cd.jpg

    I use that one from 21st Century. It's pretty good stuff. I really like the indicator and wheel which allows you to get a full revolution on the case without interrupting your measurement. I've used about half a dozen other ones, and like this one the best so far.

    The other one I'd consider is this one from accuracy one.

    concentricitygauge_home01.jpg

    I haven't used this one yet, but I might have to get it to compare against the 21st century model.



  • These are a great tool, but WHY are you using it? As in if you see that a bullet has notable run out, what do you do with it?



  • There are concentricity correction tools available.

    However, that is not the primary reason for using the tool. The primary reason is to discover conentricity problems and then find out what is causing it. You can check concentricity after various reloading steps to identify which step is introducing runout.



  • Thanks. Have you come across a situation where you had to correct runout?



  • Yes. I've been able to diagnose both seating dies and sizing dies that were faulty or had incorrect seating stems which caused runout. I've also come across poor quality brass which had horrible runout straight from the factory.



  • @orkan

    So whats the fix for the dies? Is there one?



  • New dies....
    I can tell the difference between my RCBS and forester dies .308 sizing dies. And I don't don't have a match .308 rifle.

    RLTW
    (This space for rent)

    0


  • @norcal_in_az said:

    @orkan

    So whats the fix for the dies? Is there one?

    New dies or replacement parts, depending on what the culprit is.



  • @orkan
    I'm using the Accuracy One tool. I have one minor complaint, the threaded adjustment screws are nylon and easily broken if overtightened. I replaced mine with metal screws. Here's a link to the product.
    http://www.bullettipping.com/products_concentricitygauge.html

    For correcting runout, I tried the Hornady LNL tool, which can loosen the bullet in the neck.
    I prefer this tool, http://www.bullettipping.com/products_concentricitygauge.html
    It applies the pressure to the neck, rather than the seated bullet.
    The tool only accepts small calibers.



  • @wbc

    I'm intrigued, but you posted a link to the accuracy one tool twice rather than the one used to correct runout.

    RLTW
    (This space for rent)

    0


  • Is neck turning a good solution for correcting neck runout and neck tension variances when using a bushing die?



  • @ragnarnar
    My apologies, I posted from my work place in the midst of many interruptions.

    Here is the correct link:
    http://www.neconos.com/item/Cartridge-Alignment-Tool-CAT-114

    The Website photo doesn't show the tool very well. The vertical plate is drilled with holes for a variety of calibers. You place the cartridge in the hole with the best fit, until it almost touches the shoulder, then apply light pressure to the cartridge to correct the run out. I repeat this using very light pressure several times to avoid over correcting. This is more art than science, so practice eventually improves the results. There may be better tools out there, I stopped my search after finding this one.
    I'll post a better photo of the tool tonight.



  • @wbc
    I should clarify, I only use the Neconos tool for runout caused by the cases. I apply the correction to the case neck rather than the bullet.
    I'm using Redding Micrometer competition bullet seating dies which seem to do a good job aligning the bullet. I also partially seat the bullet, then rotate the case 90 degrees and finish seating.
    I'm new at reloading so you should probably follow the advice of the experts.



  • @tpop said:

    Is neck turning a good solution for correcting neck runout and neck tension variances when using a bushing die?

    Not if you are necking only. Not using an expander leaves all the inconsistencies in your brass on the INSIDE of your neck. There are two completely separate things that are commonly referenced together. Runout is one thing, coaxial alignment is entirely another. One or both can be present. Each have different ways of being dealt with.



  • @ragnarnar

    Here are two photos of the Neconos runout tool.
    The smallest measures .200", the largest .560"

    OACdR4I.png

    Wl0MUof.png



  • Can someone provide a reference to an advanced brass prep tutorial or willing to do one? I think most guys reloading understand the basics of brass prep when reloading.
    The basics in no certain order:
    Decap
    tumble
    anneal (kind of advanced)
    size
    tumble to remove lube
    trim
    debur
    chamfer

    I can't speak for everyone who is fairly new to reloading, but I would like to know what the guys who have been doing this a while are doing. There's so many different tools and gadgets out there to buy for reloading the $ adds up quick! If you don't want to do a full blown tutorial, it would be nice to see what tools you use to give the less experienced guys an idea of what to spend their hard earned money on. Basically what "advanced tools" do you have? Annealing machine, concentricity tool, meplate trimmer, neck turning tool, ect.?



  • This will be the topic of a near future article.



  • @orkan Thanks. I think it will benefit a lot of guys starting out or guys who want to improve their reloading skills.



  • @tpop

    +1 from me.

    I'm still trying to figure the mandrel and neck turning thing out, plus the bushings and neck thickness and how they work together to yield that low runout round we're all looking for

    RLTW
    (This space for rent)

    0


  • I'm interested in any tips anyone has to minimize runout. My total indicator runout on the bullet varies greatly. I measure a few millimeters past the neck of the cartridge on the projectile using a Sinclair Concentricity Gauge and can't seem to keep it consistent. In a batch, I can get most less than 0.002" TIR with many less than 0.001" TIR but typically 10-15% of the rounds will have runout of 0.005" or greater. I get similar results with multiple brands of matched headstamp 308WIN brass regardless of the number of firings and annealings using various brands of match bullets. All brass is measured at the case neck after sizing and found to be less than approximately 0.0015 TIR so I believe the runout is being generated in the seating process. Please share any tips you have learned. I do the basics: o-ring to float the die, rotate 180 degrees after starting and/or partially seating, chamfer the case neck...Thank You!



  • @a_marks said:

    I'm interested in any tips anyone has to minimize runout. My total indicator runout on the bullet varies greatly. I measure a few millimeters past the neck of the cartridge on the projectile using a Sinclair Concentricity Gauge and can't seem to keep it consistent. In a batch, I can get most less than 0.002" TIR with many less than 0.001" TIR but typically 10-15% of the rounds will have runout of 0.005" or greater. I get similar results with multiple brands of matched headstamp 308WIN brass regardless of the number of firings and annealings using various brands of match bullets. All brass is measured at the case neck after sizing and found to be less than approximately 0.0015 TIR so I believe the runout is being generated in the seating process. Please share any tips you have learned. I do the basics: o-ring to float the die, rotate 180 degrees after starting and/or partially seating, chamfer the case neck...Thank You!

    Are you using an O-ring to float your expander assembly? Very few dies have the expanding rod running straight with the body of the die.



  • @tscustoms
    Yes, floating the die in the press and the expander mandrel in the die. But my brass is fairly concentric. Typically it's hard to see the needle move when measuring the case necks. The runout appears to be introduced in bullet seating. And again most are good but it's not consistent. I can do everything exactly the same and 10-15% are just not very concentric.



  • What press are you using?



  • @rhyno
    RCBS Rock Chucker



  • @a_marks
    Post us up a picture of how you're floating the die in a Rock Chucker? Seems like it would be very difficult to get consistent lengths as well with that set up.



  • I'll post a picture at next setup but basically, I put an o-ring under the lock nut. Square up the die then lock down the lock nut to squish the o-ring. Seems to allow the die to hold square with the press better than just locking to the press. This is for brass sizing and brass sizing doesn't seem to be the issue as the case necks are very concentric.



  • I should add that the cases headspace consistently as well.


Log in to reply