RCBS Case master. Now what? (new video)

Discussion in 'Reloading Forum (All Calibers)' started by Grimstod, Oct 26, 2014.

  1. Grimstod

    Grimstod Machinist, Designer, and Shooter.

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    So now that I have a way to see just how horribly unconcentric my ammo that I have been loading is, what do I do to make it concentric?

    I use Berger 185gr VLD Hunting bullets for most of my loading with my Forester seating and sizing dies. My brass I neck size with .001th of neck tensions using their Bushing type S neck sizing die.

    [​IMG]
     
  2. jonbearman

    jonbearman I live in new york state,how unfortunate ! Gold $$ Contributor

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    Re: RCBS Case master. Now what?

    What kind of brass are you using just for grins. Have you measured a fired case for bad runout? What kind of press do you use?
     
  3. Grimstod

    Grimstod Machinist, Designer, and Shooter.

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    Re: RCBS Case master. Now what?

    I use a Redding press and Lapua Brass. The brass is unfired. So its virgin brass. I get about .014 of runout.
     
  4. stgw77

    stgw77

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    Re: RCBS Case master. Now what?

    Sorry, but I would not thrust RCBS Case master. It depends too much on your technics how you roll cartridge on that tool...you can get false runout very very easily...there are beter tools on market to check runout (Sinclair...).
     
  5. mikecr

    mikecr

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    Re: RCBS Case master. Now what?

    You can't expect new brass to be straight(no reason for it to be). Check it again after firing.
     
  6. bigedp51

    bigedp51 Guest

    Re: RCBS Case master. Now what?

    The RCBS case mastering gauge is the Swiss Army knife of gauges and can do a lot of things but some of what it does leaves a lot to be desired.

    When you tighten the brass lock screw for the V blocks it lifts them in the air in the rear and they move up and down adding more gauge movement/runout.

    The fix for this is to anchor down the V-blocks in the rear first and then tighten the brass lock screws. to keep things from moving.

    Once you have motionless V-blocks it works very well as long as you don't drink too much coffee and don't have dyslexic fingers.


    [​IMG]

    [​IMG]

    RCBS Case Master (Upgrade)
    http://www.larrywillis.com/

    If your cases still have excess runout then you use the Hornady concentricity gauge to beat the cases into submission.
    The Hornady gauge allows you to put pressure on the bullet and bend the case neck to reduce the runout.

    [​IMG]
     
  7. Grimstod

    Grimstod Machinist, Designer, and Shooter.

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    Re: RCBS Case master. Now what?

    thanks. I noticed that they lifted up too. SO I was putting my hand on them while I tighten them down. I like the little mod you have shown. I have the tools to do it, might just as well give it a try a little later.
     
  8. artbosco

    artbosco

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    Re: RCBS Case master. Now what?

    First fireform the cases a couple times, and then measure, if you're going to measure on the bullet, only about 3/16ths ahead of the end of the case. See what things look like then. :)
     
  9. bigedp51

    bigedp51 Guest

    Re: RCBS Case master. Now what?

    Look at my closeup photo of the V-blocks, once you rotate enough cases you will wear through the paint on to the soft aluminium V-blocks. Once this happens you will need to lube the V-blocks, if you don't lube the V-blocks you will find out how disk brakes work while slowing the rotation of the case. (and adding to case wobble)

    After this you will have constant dreams of buying the Sinclair concentricity gauge that has hard ball bearing for the case to "glide" on.
     
  10. zipollini

    zipollini Silver $$ Contributor

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    Re: RCBS Case master. Now what?

    Something to dream about :)

    http://www.accurateshooter.com/gear-reviews/new-wheel-drive-concentricity-gauge/

    http://www.bullettipping.com/products_concentricitygauge.html

    http://www.bullettipping.com/media_video_concentricitygaugedemonstration.html
     
  11. Grimstod

    Grimstod Machinist, Designer, and Shooter.

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    Re: RCBS Case master. Now what?

    Ya i would love to have one of those. But the price tag is so much.
     
  12. Grimstod

    Grimstod Machinist, Designer, and Shooter.

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    Re: RCBS Case master. Now what?

    I have been doing a little more reloading and started to do something that an article on the bulletin suggested. I seat half way then turn the bullet 180 then seat it the rest of the way. I have seen a slight improvement.
    However one interesting revelation was when I started moving the rest that you rotate the bullet on, up and down the shell. With the rest on the shoulder I get the 12-15thousanths of runout. But when I put the rest on the neck I only get like .003 What does this mean?
    This is all Virgin brass. I have only neck sized it with a redding Type S Bushing necks sizing die. I seat my bullet with a Forster micrometer die.
    [​IMG]
    [​IMG]
     
  13. dkhunt14

    dkhunt14

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    Re: RCBS Case master. Now what?

    If the necks are not turned the bullet is sitting off center and will have run out. The case neck should come out of the gun and size and be little to no run out. Check them out of the gun after fired and check again after sizing. Matt
     
  14. Matt in Virginia

    Matt in Virginia

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    Re: RCBS Case master. Now what?

    fwiw,
    I've been using the Sinclair Concentricity Fixture with a Starrett Dial Indicator for 10 plus years with no complaints. That said I plan to pick one these up shortly. More than likely use with one of my Interapid Indicators... Neat design.

    I would concur on the quality of the RCBS unit. It is to concentricity indicators what RCBS Dies are in the world of dies. They can get you through, however, for more money you can buy a far better product...

    Regards, Matt.
     
  15. Grimstod

    Grimstod Machinist, Designer, and Shooter.

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    Re: RCBS Case master. Now what?

    Well put Matt.
    I think it will get me by for now. I still need lots of practice and I also need to shoot a lot more to justify one of the nicer ones. All in good time I guess.
     
  16. Grimstod

    Grimstod Machinist, Designer, and Shooter.

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    Re: RCBS Case master. Now what?

    dkhunt I will clean up some of my brass that I have fired once. Will be interesting to see if I get better concentricity with fire formed brass.
     
  17. amlevin

    amlevin

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    Re: RCBS Case master. Now what?

    I have the RCBS Case Master and for a while it gave me fits.

    Took a while to realize what was causing the problem. Almost all rifle cases with a shoulder also have a taper in the body of the case. When rotating the case with the case head fully against the vertical stop on the LH V-Block I happened to notice that the case was being moved Left and Right by some runout on the case head extractor rim. As the case moves left/right the gauge will be moved up and down as the taper runs across the RH V-Block.

    I plan on modifying the LH V-Block so the "Stop" is a small pin that contacts the case in the primer pocket (center) or on the primer of a finished case. Any run-out near the axis of the case will be nominal and won't cause the significant "false runout" the current stop does.

    I need to get one of these before I can stat the modification though:

    [​IMG]
     
  18. Grimstod

    Grimstod Machinist, Designer, and Shooter.

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    Re: RCBS Case master. Now what?

    Please do report back on this. I lift even give this a try since my cartridges of choise have a lot of tapper.
     
  19. Joe R

    Joe R Silver $$ Contributor

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    Re: RCBS Case master. Now what?

    I made my own high tech bullet straightener. First I mark the apex of the runout and then put in the hole and give it a bit of pressure. I repeat until I get it within .001 to .003.
     

    Attached Files:

  20. brians356

    brians356 Gold $$ Contributor

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    Re: RCBS Case master. Now what?

    How much runout before straightening?

    I'd like to see a report on any accuracy improvement you find between straightened and un-straightened ones. Please update if you happen to do any such testing.
     

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