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Bullet seating variance

Discussion in 'Handloading and Reloading' started by Ohsobad_chevy, Jan 5, 2012.

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  1. Ohsobad_chevy

    Ohsobad_chevy Member

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    I am fairly new to reloading (.243). I have a rcbs rock chucker with rcbs full length dies. I am loading 65 grain v-max and 70 grain Berger HP. I am having problem with the cartridge overall length. With both bullets it seems to seat them differently. I am having as much as 12 thousandths variance in my overall length. I am using new wincheater brass and i noticed it wasn't perfectly the same in length to start. What could cause this much variance in overall length of my loads?

    Also, i was reading about crimping. My dies can be set for crimp or no crimp, but the instructions were not very clear to me. Do I need to crimp my loads?
     
  2. Walkalong

    Walkalong Moderator

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    Not unusual, although .012 may be a bit much.
     
  3. kelbro

    kelbro Member

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    It's the seater plug. Long pointy bullets that don't match the seater plug can't seat consistently.
     
  4. Blue68f100

    Blue68f100 Member

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    With 2 different bullets I would expect 2 different lengths. The profile between the 2 are different so will require an adjustment to the seater. Any time you change bullets even if there the same weight from different mfg you will get a different length if you do not adjust your seater.
     
  5. gamestalker

    gamestalker member

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    Unless by coincidence, no two bullets of different manufacturer or part #'s will seat to the same OAL. OAL really means little, it's the distance off the lands and olgive that is most important provided the rounds fit the magazine and fed reliably.
     
  6. Ohsobad_chevy

    Ohsobad_chevy Member

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    I failed to mention that I did reset the seater plug when I switched to the berger bullets. Loaded the first one to spec and the additional seats were varying as much as 12 thousandths.

    I am fairly new to rifle loading so forgive me. I'm trying to learn as much as possible in a short time.

    Do I need to get a different seater plug for my die to load ballistic tip V max?

    As far as crimping goes? Do I need to crimp my loads?
     
  7. 243winxb

    243winxb Member

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    Overall Length (OAL) Variation

    No.
    .005" variance is about normal for me. It could be how you measure it . Lee Info >
     
  8. Gonzofam

    Gonzofam Member

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    I would say yes that happened to me also. I started bumping the bullet in twice so as to give the bullet a chance if it is a little crooked to straighten out. I also use a hornady comparator since polimer the tips of those specific type of bullets make your COAL measurements off round to round. With a comparator you measure the ogive of the bullet which will make your reloads more exact to what you want. That is if you ( here is where the wording gets many different opinions) ODRIV the specific rifle, for that specific bullet. Empty casing fireformed in your specific rifle. ReChamber it slowly with a fresh bullet to find where it makes contact with the lands and grooves. Back the bullet off a thousandth to start. RESEARCH THIS PROCESS BECAUSE THE WAY I HAVE EXPLAINED THIS IS VERY BRIEF AND HAS SEVERAL LONG EXPLAINATIONS ON HOW TO DO THIS. Then get a comparator reading. If you are just under COAL, and with the comparator you should be
    able to get to.003 . You'll have a good controllable, consistently producible round. That's what has given me outstanding results. Of course follow reloading manuals close.
     
    Last edited: Jan 5, 2012
  9. 2 Wild Dueces

    2 Wild Dueces Member

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    Measuring rounds, from the case head - to the tip of the bullet, can give significant variations. The variations are mostly due to bullet tip variations resulting from the manufacturing process. While the bullet's tip lenth may vary the rest of the bullet's shape should be quite uniform.

    The best way to measure loaded rounds is to use a bullet comparator which allows the measuring off the bullets ogive. When measured in this manner variations should be less than .001".

    A bullet comparator can also be used to check for variations in bullets - from the base of the bullet to a datum line on the bullet (an arbitrary circle along the bullets ogive). If you find variations (which is quite rare) I have found that it's near impossible to get those bullets to shoot accurately.
     
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