RCBS .40S&W carbide seater die trouble

Discussion in 'The Ammo & Reloading Forum' started by bmg50doorgunner, Jan 24, 2010.

  1. bmg50doorgunner

    bmg50doorgunner New Member

    Jan 24, 2010
    When I seat my bullets I get a “ring” or an impression around the nose of the bullet. The bullet seats to accurate depths and with very little effort exerted on the handle of my press. I am using a Rock Chucker single-stage with RCBS .40S&W carbide die set. Per the RCBS die instructions I am not crimping. My seating depth is 1.120” with a tolerance of +/- 0.0005” … darn-near perfect. I’m new to reloading, but let me say that I have thoroughly read the Speer and Hornady reloading manuals (cover-to-cover) as well as the die set instructions. The RCBS website features this very problem in its FAQ section and recommends that the user purchase a custom-order die from its Special Order Catalog and send in your bullet to RCBS for a match.


    Bullet: Speer 165 gr. TMJ FN (This is a FMJ flat-nosed projectile)
    Brass: Win, Federal, PMC, Blazer, etc.
    Primer: Irrelevant
    Powder: Irrelevant

    Do you think it’s likely that such a common die (RCBS .40S&W carbide) would have problems with such a common bullet? It’s not like I’m trying to reload a custom-cast lead projectile. Is it common for seater dies to leave impressions on bullets? I’ve also tried loading 165 gr. frangibles, which have a more rounded nose, but get similar impressions left by the “cup” of the seater plug. Is there a better die out there? I’m about to give up on this RCBS seater die and try a Lee substitute. I don’t see how I could be adjusting the seater die incorrectly if I’m getting such precise seating depths. Again, I am not crimping. Any other ideas???

    Thanks for looking,
  2. muddober

    muddober Active Member

    Sep 19, 2008
    Carson City Nevada
    There is nothing wrong with your RCBS stuff. All you need is a flat nose bullet seater plug. If you have access to a lathe you can make one out the existing seat plug you have. Take out the seat plug and take a look at it and you will see what I mean. You need to take the "cup" off of it. It sounds to me you somehow wound up with a round nosed bullet seater plug. The carbide portion of your dies is only in the sizer die, meaning that the seater dies are the same for carbide or non carbide.


  3. 312shooter

    312shooter Well-Known Member

    Mar 17, 2008
    Las Vegas NV
    I have seen these rings occur in plated bullets such as berry's and rainer but not a jacketed. Before we go blaming your seater plug are you belling the case mouth properly before seating? I think I'd increase the bell on the case mouth a bit more, dollars to doughnuts your "ring" fades away with the correct amount of expansion in the case mouth. I think this is the only thing that would cause resistance enough to imprint a jacketed bullet other than the incorrect diameter bullet, or as I said it is a plated bullet and not actually jacketed.
    Last edited: Jan 25, 2010
  4. bmg50doorgunner

    bmg50doorgunner New Member

    Jan 24, 2010
    Gents, thanks for taking the time to reply!

    312shooter, I really thought you had my problem nailed. I re-checked the depth of the expander die and found I was only going about 1/2 the length of the protruding expander. I re-set the die and case flared the cases to the full depth of the expander. I then seated 6 more bullets. While the bullets slid in a bit easier, I am still getting that nasty ring imprinted on my bullets. [See photo].

    Muddober, I think you're right. I think I'm gonna have to mill down the "cup" to a flat surface - or just try different bullets.

    Attached Files:

  5. rocklinskier

    rocklinskier New Member

    Aug 16, 2009
    Have you tried using the other seating plug? the one that is for round nose projectile that comes with the set? I'm assuming that there is one. I don't have the .40 set so I may be incorrect,(the .45 and 9mm have two seat plugs) but if there is one, it might be worth a try before modifying the flat/swc one.

    Not the expert on this, so it is only a suggestion.
  6. res45

    res45 Member

    Sep 21, 2007
    The Speer bullets have a slightly softer copper jacket the TMJ's as similar to the Speer GDHP's which are basically a fancy plated bullet just better quality,I shoot Speer and Berry's so I'm not knocking either one.

    The seater plug in most pistol reloading dies are pretty generic,designed to be used with a variety of bullets,I got the same ring when I tried some Speer GDHP's in my 9 x 19 Mak. The seater plug just doesn't fit the profile of some bullets very well so hence the ring. One thing you can try and it works on some plugs is to take some valve grinding compound and the bullet your using and use it to polish the inside of the seater plug and smooth out the inside edges.

    ADDED: If you have a dremal tool and some of those soft buffer wheels and some buffing compound you can use that also,it does a nice job of polishing up sharp edges.
    Last edited: Jan 25, 2010
  7. Claude Clay

    Claude Clay New Member

    May 26, 2009
    Central CT
    what res said--

    touch it to a grinding wheel; take of a bit (perhaps 1/2 mm) and than bevel
    the inner edge.
    repeat if necessary.
    comes under the heading of 'some minor fitting may be necessary'

    good luck
    and kudos for having such a clean work area
    i rather have forgotten what one can look like......
    Last edited: Jan 25, 2010
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