bullet comparators

Discussion in 'Equipment Discussions' started by Jimm, Jul 6, 2005.

  1. Jimm

    Jimm Writers Guild

    Jun 12, 2007
    I have two of them from Sinclair. You know , the ones that have holes all around them,stick the loaded round in appropiate hole, then mic. Both of the comparators have diff calibers on them, however they both have 30 cal on them.

    Guess what ? they don't mic the same!

    About .004 diff.

    What gives ? I thought these things were a lot closer than that .

    I know this is equipment review but what is out there that I would feel a lot better about using? i.e. repeatable readings. Please , start a post on this wherever it's appropiate.

    Thanks a mill, Jim
  2. Centre Punch

    Centre Punch Well-Known Member

    Oct 29, 2004
    Hi jimm,
    remember this, they are comparators designed to compare the length of your loaded rounds and as you know if you get different readings, your bullet seating depth will be at fault.
    Theoreticly, do the same with the one which is 004" bigger and again you will find that if you have different reading your bullet seating depth will be at fault.

    You could say it is like measuring a given diameter with 2 micrometers, 1 new and 1 old, worn and out of calibration, you are going to get 2 differing readings.
    I use the Stoney Point version that clamps onto the blade of your Vernier calipre and has interchangeable calibre specific bushings.


    "I mean't to shoot the pike but the duc got in the way"