Base to ogive measurement tool that doesn’t wander

Discussion in 'Reloading Forum (All Calibers)' started by dbduff, Mar 22, 2020.

  1. dbduff

    dbduff Gold $$ Contributor

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    Trying to measure base to olgive with Sinclair tool, both the mechanical $30 gauge and the $115 electronic gauge, both wander after 15 plus measurements. Take a bullet,make it your base measurement, measure rest to compare same or differences. After measuring 15 or so, big differences begin to appear between your reference measurement and the rest. Recheck your reference measurement, originally set as .oooo now it’s .ooo5 wtf? Am I lost in the weeds, asking too finite a question for the tool? How much variance in base to olgive is “excessive” ? Stumped. Me or the tool?
    D
     
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  2. PopCharlie

    PopCharlie Silver $$ Contributor

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    Is the comparator clean? I have found crud in the end of a seating stem more than once.
     
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  3. rsmithsr50

    rsmithsr50

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    my guess is you are using a digital caliper the READS to .0005, but is actually only ACCURATE to 0.001
    buy a better tool
     
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  4. R.Morehouse

    R.Morehouse

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    I like the unit from Holland. I find it easy/fast to use and very repeatable. Check out his Youtube vids on the product and sorting expectations.....;)

    Regards
    Rick
     
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  5. 338 dude

    338 dude Gold $$ Contributor

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    A half of 1 thousandth of an inch is not that much that can be just the pressure you’re putting on your caliper with that said calipers are not as accurate as everyone thinks if you’re going to be super accurate and consistent you’ll need a quality made micrometer
     
  6. 47WillysGuy

    47WillysGuy Gold $$ Contributor

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    knD[/QUOTE]
    I believe it's all in the touch. Take a known standards and measure them (feeler guages) and see if you get the same reading as printed on each of the feelers. Take a set of feeler guages apart, scatter them on a table and starts measuring without looking at the number printed on the guage. Are you getting the same value as printed on the guage.

    Or play a game, take the guage set apart, mix them up and see if you can put the set back in order with the venier.

    I have a 30 dollar venier and don't trust it.
     
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  7. Texas10

    Texas10 Gold $$ Contributor

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    Is your battery fresh in the electronic caliper? I use a Mitutoyo that drifts wildly between the 3 and 4 inch margins when I use the headspace gage. Quite frustrating. While I am pretty sure it's not a Chinese knockoff, I can't be sure. Amazon sells them cheap, look identical, but are Chinese. I don't remember where I got if from, so it may be a cheap knockoff. I re-zero frequently.
     
  8. Kurz

    Kurz

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    Sometimes we have to step back and examine what's really going on but you need some experience and expertise to move on critically.

    We all benefit from the expansion of inexpensive measuring tools, but these same inexpensive tools can mislead us and put us to sleep with regard to accuracy as mentioned above. You cannot expect a $15 pair of calipers to resolve the same degree of accuracy as does the $500.00 pair which comes with complete certification. But, with calipers as opposed to micrometers, touch and feel play a major role. Learn how to use the tool consistently.
     
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  9. dbduff

    dbduff Gold $$ Contributor

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    I’m rezeroing every 10 pieces. Pita as it slows down what should be an easy peasy endeavor.
     
  10. dbduff

    dbduff Gold $$ Contributor

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  11. Doubs43

    Doubs43

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    Does anyone else use the Hornady comparator?

    I use it with a dial caliper and keep everything within + or - .001" or less.

    One additional thought. If your Sinclair tool is electronic and drifts, is it being caused by florescent lights or other electronic interference? I use a scale that's accurate to within .02 grains and I have to be careful about interference or it will drift.
     
    Last edited: Mar 23, 2020
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  12. dbduff

    dbduff Gold $$ Contributor

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    thanks, got the caliper issues. I’m using Sinclair dial indicator on their comparator stand, no calipers involved. Came with mechanical dial indicator that wandered and I replaced it with an electronic indicator guaranteed for life, hence the $130 price tag. Replaced battery when it first started to wander, which helped. But it still wanders. Am trying to figure out if dial is correct and measured surfaces are changing or if anvil and comparator opening get contaminated with bullet residue enough to effect the measurement. Open to suggestions. Using designated bullet as “.0000” I had assumed that measurement would stay as a constant. It hasn’t and that perplexes me. Is it the the tool or operator error at play?
     
  13. Ned Ludd

    Ned Ludd Gold $$ Contributor

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    My guess is that the problem lies in the anvil. If you're not happy with zeroing before every bullet, I would call Sinclair and find out whether they believe this behavior is normal, and if it can be cleaned and/or lubed in some way. If you're using the one I think you're using, it likely has the exact same dial indicator and anvil found in their concentricity gauge, which I have. I have not noticed the kind of wandering zero you're describing in the concentricity gauge. Then again, I'm not using it with large numbers of cases as you probably are doing when sorting bullets. The mechanism by which the anvil works doesn't strike me as being highly reproducible, so maybe frequent zeroing is to be expected.
     
  14. dbduff

    dbduff Gold $$ Contributor

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    Will try with fluorescent lights off. Thanks for suggestion. Simple things first!
     
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  15. rardoin

    rardoin Silver $$ Contributor

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    I have a Buhay unit (similar to the Sinclair). I can take a single bullet, drop it in the appropriate caliber comparator and measure with the DTI. I can take the same bullet and wriggle it slightly and the reading may change 0.001-0.002"...sometimes a little more. I can lift the bullet, turn it 180deg, reseat it and measure and it will vary. I can get the same variation by measuring it with a Hornady comparator and a Mit caliper. In my hands I find a bit of variability in bullet BTO measurement due to the small area of contact with the ogive and potential 'tilt' of the bullet while touching off on the base. Perhaps this is what you are experiencing. I'm sure I am the only one who has experienced this;).
     
  16. dbduff

    dbduff Gold $$ Contributor

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    Will look at anvil as you suggest. I believe the dial indicator I’m using is the one you describe on the concentricity gauge. Will contact Sinclair if this continues. Thanks for response.
    D
     
  17. Ackman

    Ackman Silver $$ Contributor

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    As unlikely as it soundss, I've found large, sometimes huge, ogive length variations within a box of bullets. Years. ago loading a big batch of 50BT's I got some that were seated up to .030" from where they should have been. Had to be something to do with the die, right? After screwing around with that and finding nothing wrong, I started checking bullets. Couldn't believe the variation within that one box. Then checking a bunch of 6mm BT's and found pretty substantial variation within those also. Made me re-think about seating .005" off the lands. I've also found variation, more than just a couple thou, within a box of Sierras. This was all probably 20yrs ago, but I haven't forgotten that bullets can vary.
     
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  18. Doubs43

    Doubs43

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    Bullet ogive variation can be a problem as you suggest. Loading 77 grain, .224 Nosler Custom Competition bullets for .223, I've noted as much as .005" difference between bullets. Similar variations have been noted with Nosler 52 grain Custom Competition bullets. I've experienced less variation with Sierra 69 grain Match King bullets but still find some as much as .003 ~ .004" differences. Fellows I shoot with have reported similar variations with Berger and other brands. I guess it's fairly standard.
     
  19. Ackman

    Ackman Silver $$ Contributor

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    I use a no longer available Davidson ogive checker.
     
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  20. Dusty Stevens

    Dusty Stevens COVFEFE- Thread Derail Crew Gold $$ Contributor

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    You really need to be measuring to the .001. Just your body heat will change a bullet more than .0005. Also you need a tool that has an ojive in it instead of a sharp hole to measure with. Measure the point your chamber will measure it by. Measure just any point on that bullet, hold it in a closed hand a while then measure again. We dont work to the half thou or the ten thou in the gun world we measure to the .001, since we dont have a lab and all.
     
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