How does a seating die work.

Discussion in 'The Basics, Starting Out' started by samson, May 6, 2003.

  1. samson

    samson Well-Known Member

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    Does a seater die seat the bullet from the ogive or the tip of the bullet. Maybe it is just me or my equipment but the col is always different(most of the time). I am just using an RCBS seater die (not competition). Do any of you have any suggestions.
     
  2. Mysticplayer

    Mysticplayer Writers Guild

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    If you take the die apart, you will answer this question. The seating stem is hollow. The bullet nose fits into this space and then pushed into the neck of the case.

    Since this diameter is in a different locations in different bullets, it is possible to seat different brands of bullets to different OAL.

    If seating softpoint bullets of the same brand, different OAL also can occur due to the amount of exposed lead. Some noses get knocked shorter.

    Measure OAL using the ogive of the bullet. Sinclair makes a neat tool that works with a vernier caliper. simple and accurate. You should find that the OAL measured this way is basically the same. If not, tighten the screws on the seating die and/or change bullets.

    Good luck...

    Jerry
     
  3. samson

    samson Well-Known Member

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    Jerry,
    I have the sinclair comparator and am noticing that it is making a mark on the bullet,no matter how lightly i use it. Do you have any suggestions?
     
  4. Mysticplayer

    Mysticplayer Writers Guild

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    Take some fine sandpaper and rub the edge of the hole in the comparator. There might be slight burrs from the machining.

    Any light marks on the bullet will not affect its performance. Just be consistent.

    Jerry
     
  5. john g duvall

    john g duvall Well-Known Member

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    May I suggest that you first find out the exact distance between the ogive to the lans and grooves that give you the greatest performance(tightest group). This will include using the correct combination of brass, powder load, primer and bullet. Using your bullet comparitor in conjuction with the Digital Micrometer and charting your hit patterns will in time give you the correct measures you desire. It is a very specific science. Reloaders all have different opinions about what to use. Increase or decrease your powder loads in increments of 1/10 grain using 5 shot groups to determine what works best for your weapon.