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Comparator: Did I just waste $70 for nothing?

Discussion in 'Handloading and Reloading' started by berettaprofessor, Feb 21, 2019.

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Do you EVER use a bullet comparator to load rifle cartridges?

  1. Yes, a Hornady Comparator

    29 vote(s)
    51.8%
  2. Yes, Sinclair or other

    5 vote(s)
    8.9%
  3. No, I used to, but stopped because it didn't matter

    3 vote(s)
    5.4%
  4. No, I've never bothered to try one

    17 vote(s)
    30.4%
  5. Other, explain below please

    2 vote(s)
    3.6%
  1. berettaprofessor

    berettaprofessor Member

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    So, after reading a number of comments here and elsewhere about the importance of seating bullets to a consistent bullet ogive length rather than overall tip length, and wondering what I was missing as an easy aid to precision, I purchased a Hornady Comparator kit (full) ($55) and the Hornady Anvil ($15) for the other side of the caliper. Receiving it yesterday, I measured 10 random cartridges of 224 Valkyrie I recently loaded (from a group of 50, measuring OAL to the tip at the time of loading) and got the following:

    upload_2019-2-21_10-12-1.png

    Some specifics: All cartridges were loaded on a single stage Lee Breech with Lee 224 Valkyrie dies and the goal of a 2.260 OAL. Bullets were Berger VLD target 90 grain 224's. Measurement is with a Fowler Premium caliper, analog type. For the number-oriented types here, the means, etc for this 10 cartridge group were:

    upload_2019-2-21_10-18-44.png

    I recognize that my OAL spread is higher than I'd like it to be. Some of that may be the nature of the Lee seating dies without any micrometer adjustment, but most of it is simply that I need to be more careful with what I accept for OAL length as I'm loading. Currently, I check OAL every 10-15 cartridges and adjust as I go, so these 10 cartridges pulled from a group of 50 also represent several adjustments to keep things closer, or so I thought. I've been content with a ±0.005 or so in OAL, but I maybe need to tighten that up.

    But, as far as the comparator, it looks to me like the measurement of OAL to the bullet tip provides a pretty good consistent ogive length as well, leaving the ogive range at only 0.003 spread. That's better than the spread of OAL which I believe is likely just that the Hornady Comparator and Anvil are more consistent surfaces to measure from than me trying to put a small bullet tip squarely in the caliper; i.e. I think the larger spread is due to more measurement variation rather than actual OAL difference in the cartridges.

    Feel free to disagree, but I'm pretty satisifed with an ogive spread of 0.003 and I'd find it hard to increase my loading time by trying to keep ogive length down using the comparator more frequently than I measure tip OAL now. What would you do? Comparator or not? How heavily do we need to chase the Precision Fairy?


    Addendum: As another check, I compared OAL and ogive on 5 cartridges of 308 Winchester, loaded with Hornady 168 grain Match to 2.775. The numbers and statistics were similar to the 224, although with the 308Win, my OAL was more consistent than the ogive measurement:

    upload_2019-2-21_10-34-50.png
    upload_2019-2-21_10-35-21.png

    Based on these numbers, would you dramatically change your loading practices to include the comparator?
     
  2. ArchAngelCD

    ArchAngelCD Member

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    It looks like you are producing very good ammo. You probably didn't need that took for this cartridge.
     
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  3. Muddydogs

    Muddydogs Member

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    Whats the tip of the bullet? Exposed lead, hollow point, plastic tip? Sure your going to get consistent OAL measuring to the tip of a hollow point bullet but not so much with a lead or plastic tip. Premium bullets will give you a better reading to the tip then some bulk 1000 pack of bullets as well.
     
  4. berettaprofessor

    berettaprofessor Member

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    Both these bullets are copper-jacketed including the tips. I wondered if the lack of variation is simply that they are pretty premium bullets and probably above average quality; but at the same time, if we are chasing accuracy, who's going to use a lesser quality bullet?
     
  5. berettaprofessor

    berettaprofessor Member

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    As a companion to my other thread about recently purchasing a comparator and now questioning whether I need one, I thought this poll would provide good information towards how many reloaders use them.
     
  6. edwardware

    edwardware Member

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    Yes, a Sinclair comparator. All my COAL data is recorded on an ogive basis, because that's the most meaningful measurement to cartridge performance once you're below Mag Length, if applicable.
     
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  7. Blue68f100

    Blue68f100 Member

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    On my precision loads I go by the ogive measurement. I record this in with my load data. Every time I get a different lot of bullets I use it for my reference. I've seen a difference between lots which required an adjustment. 0.010" swing is rather larger in OAL if that all your going by. I've seen 0.003" variation in ogive cause a group open up.
     
  8. HJ857

    HJ857 Member

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    Same for me. I use the Hornady though. One note, with the Hornady system measurements are not transferable to other people's gauges. Each one seems to have surprising variances, so your measurements with your gauge are yours alone.
     
  9. Rule3

    Rule3 Member

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    A "fun" video.:)

     
  10. forty_caliber
    • Contributing Member

    forty_caliber Contributing Member

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    The comparator measurement is more valuable when used in conjunction with a OAL gauge and a modified case. This allows you to transfer the measurement of where the bullet meets the lands of YOUR rifle to the bullet seating die. COAL vs CBTO.



    .40
     
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  11. ohihunter2014

    ohihunter2014 Member

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    I use one because I use the Hornady OAL tool for seeing how far from the lands I am. I wonder with your couple thousandths difference if your not running the ram all the way up or running it too far up and its seating deeper or even if case length would have something to do with it. Either way unless your close to the lands IMO i wouldn't worry about it. I do because I'm close to the lands and have a short throated rifle so I need all the help I can get.
     
  12. otisrush

    otisrush Member

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    If I missed it in your post I apologize - but are your current methods producing the accuracy results you want? (i.e. Did you head down the comparator route because you were curious how consistent your ammo measured or were you seeking out getting improved performance on target relative to what you've been able to get?)

    Your .223 results don't surprise me. I'm "saying more than I know" (which is my funny way of saying I'm not 100% in what I'm about to say) but my understanding is that bullet manufacturing processes are such that the profile from ogive-to-tip (meplat?) is inherently less consistent than bullet base-to-ogive.

    Your .308 results do surprise me. I wonder if the .223 bullet is a better fit for your seating die than you .308 bullet is?

    I use a comparator for my precision rifle rounds but not my plinking ammo. I've also found a component of getting even the ogive measurement consistent is the amount of force I place on the press handle at the bottom of the down stroke. I try to get my seating die set so that I'm about .001" too long if I let the press handle bottom out and put no downward force on the handle. (It's a RCBS Rock Chucker.) I can (if I recall correctly) shorten that ogive measurement by an incremental .003-.004" based on how hard I push down on the handle after it has bottomed out.
     
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  13. Shanghai McCoy

    Shanghai McCoy Member

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    Nope, never used one.
     
  14. Chuck R.

    Chuck R. Member

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    I use a Hornady, with Sinclair inserts for a couple of my precision calibers.
     
  15. Whiterook808

    Whiterook808 Member

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    I use the Hornady to check consistency of COAL withing a batch.
     
  16. .308 Norma

    .308 Norma Member

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    I voted "No, I've never bothered to try one" in your poll. Almost all of my rifles are hunting rifles...MOA is plenty "good enough" for me when it comes to hunting, and I can get that with every scoped rifle I have without a bullet comparator.
    Possible exception...I have a brand new 264 Win Mag that I haven't been able to get out and shoot yet, so I don't know if it will go MOA or not with the bullets I want to use for antelope hunting. However, if it won't, I'm more likely to sell the rifle than buy a bullet comparator.
     
    Last edited: Feb 21, 2019
  17. Blue68f100

    Blue68f100 Member

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    I use a different gauge (Hex nut design for 6 calibers) but like the others have to fit magazine if required.
     
  18. otisrush

    otisrush Member

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    I use the Hornady gauge for my bolt guns - which I use as single shot only.

    The mag is my OAL gauge for my AR. :)
     
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  19. WelshShooter

    WelshShooter Member

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    Knowing your ogive length is really useful when you try different bullets and don't care about magazine length. For example, I shoot both 123gr Hornady A-Max and 123gr Lapua Scenar bullets in my 6.5x47 Lapua. When I load up some ammo with both bullets, I get very different overall lengths between the two types of bullets but my base to ogive length is almost identical between tho two bullets as I've set my dies up specifically for this. I don't bother to measure overall length anymore on these rounds, I just measure base to ogive (I use 308 AI mags and the 6.5x47 Lapua is a fair bit shorter than 308 so I know I won't exceed mag length).

    The question as to why your base to ogive length is so consistent but your overall length isn't, is very likely due to the meplat on your bullet tips. Although bullet mass on match quality bullets like Lapua Scenar's and Berger VLD's are very consistent, the meplat (open nip on the bullet) is not very consistent. Some may question if this really matters and some people go through the trouble of trimming the meplat to a uniform length and re-pointing the meplat.

    In short, I don't think it was a waste of your money or time. You've just learned that you are making good, consistent loads and the reason why your oal is varied is likely due to the meplat. If you're trying different seating depths to get the best "jump" to your rifling, you can record this measurement and transfer it to any other bullet you wish to use. I'd set your dies up once for correct base to ogive length and don't bother adjusting it throughout your loading process.
     
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  20. WelshShooter

    WelshShooter Member

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    I use a comparator made by a fellow Brit here in the UK. I have a set for 223 rem and 6.5x47 Lapua bolt guns. These comparators work in conjunction with some shoulder bupm gauges which can be used to measure how far case shoulders are pushed back during full length sizing and thus adjust your dies to minimise this amount.
     
  21. Walkalong

    Walkalong Moderator

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    I sometimes use a comparator.
     
  22. RandyP

    RandyP Member

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    For all my MOE (Minute of Earth) plinking AR ammo, I've not found the need for one. I was promised there would be no Math - lol
     
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  23. Whiterook808

    Whiterook808 Member

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    For me it is just quality control check, largely on myself. I check consistency of the COAL and run out. I think a lot of the variances are introduced if the equipment is not operated in a consistent manner. You need feed back if you are going to correct your techniques.
     
  24. berettaprofessor

    berettaprofessor Member

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    Great question Otisrush. I was fine with the accuracy at present for most calibers I load but reloading is certainly just an interesting hobby to me so I am always experimenting/trying to improve. With the 224Valk I'm getting ready to try longer distance and so thought it'd be worth a try to wring whatever I can out of them. In other words, it wasn't necessary, but seemed like a good waste of my time and money.:D
     
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  25. 243winxb

    243winxb Member

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    Last edited: Feb 21, 2019
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