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OK, I chrono'd some rounds, now what?

Discussion in 'Reloading' started by XDRoX, Mar 14, 2010.

  1. XDRoX

    XDRoX

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    Well for those of you that remember, I got some crazy readings a couple weeks ago because I was standing too close to my chrono. Today I tried again from about 20' away.

    Here's one of my groups:
    1030
    1104
    1091
    984
    1064
    1104
    1092
    1023
    905

    If you're wondering why there are only 9 entries it's because the first shot hit the chrono:crying: It wasn't that bad though. I was able to repair it.

    So, from the above data:
    Mean: 1044.1
    Standard Deviation: 66.8

    If I drop the high and low then:
    Mean: 1055.4
    Standard Deviation: 44.4

    My question is do you guys drop the high and low? Also, every now and then (about every 10 shots) I got readings in the 1500's or 800's. Can I assume they are chrono misses or "blast caused" errors and ignore them?

    They shot really accurate and the felt recoil was minimal.

    I was shooting 9mm:
    1.150" / 5.0gr of WST / 124gr TMJ RN (plated) / IMI brass / CCI primers
    And shooting them out of a 4" XD.
    I can't really compare my data to any manuals because WST data for 9mm is hard to find.

    Comments or anything else I should be doing is appreciated.
     
    Last edited: Mar 14, 2010
  2. WiskyT

    WiskyT Malcontent

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    That certainly doesn't help things. Why only 10 shots and at only one position? 20 feet seems to be working better than your last trip if I remember correctly, so why didn't you try 30 feet?

    And no, you don't throw out the highs and lows unless you are a democrat and want to show how the Earth is warming. Either your loads are not consistent, or your chrono isn't set-up or opperating properly.

    Your ES should be somewhere in the neighborhood of 50-75, better isn't harder to do. Your SD should be somehwere around 30 or better. SD of 15 or better are common with pistol ammo.
     

  3. XDRoX

    XDRoX

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    I only loaded 10 of each in case of problems. I didn't want to pull a bunch of rounds. And the 30' comment, come on, I hit the thing at 20', I didn't think the chrono would make it home at 30':whistling:

    Thanks about the high and low thing, I'll include all the data. What is ES and SD? I assume SD is standard deviation, but not sure about ES?
     
    Last edited: Mar 14, 2010
  4. PCJim

    PCJim Senior Member

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    I agree with Whisky (why isn't there an "e" in Whisky?) on your results and with the inclusion of all rounds fired of that particular loading.

    The SD is standard deviation and, as WhiskyT stated, should be much lower for a pistol round. Your ES or extreme spread (highest velocity minus lowest velocity) is very high at 199. This would indicate that there was a lot of inconsistency in your reloads. This could be the result of inaccurate powder charges, different mfg brass, varying primers, varying COL, etc. If you get your ES down to a more reasonable number.

    FWIW, I ALWAYS use the same mfg brass and trickle charge my loads when developing a new recipe - you need to keep as much consistancy as possible.

    ETA - there isn't a "h" is WiskyT, either???
     
    Last edited: Mar 14, 2010
  5. XDRoX

    XDRoX

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    Thanks for the advice Jim and the explanation of SD and ES.
    I did use the same brass/primers and trickle loaded every round. Therefore I don't think the rounds could of had that much inconsistency in them.

    I guess I have to assume I was too close to the chrono again.
    I guess I'll have to do what Wisky suggests and move back more.
    Say a prayer for my chrono:supergrin:
     
    Last edited: Mar 14, 2010
  6. GioaJack

    GioaJack Conifer Jack

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    You must really be bored... now you're delving into the depths of 'grammar police. Well two can play that game.

    How come your screen name isn't spelled;

    PeeSeaJim

    or

    PeaSeaJim

    or
    PeeSeeJim

    or

    PeaSeeJim

    or

    PCGym

    or

    PeeCGym

    or

    PSeaJim

    or

    oh screw it... I'm gonna go drink some Wisky... er... whiskey.

    Oh God... please, please, at least show a NASCAR rerun today... oh, hey, look... Blackhawk down is on... cool, I'm gonna watch that. :supergrin:

    Jack
     
  7. XDRoX

    XDRoX

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    Damn Jack when I saw you posted to my thread I was hoping for some words of wisdom regarding me learning to use a chrono.

    At least you made me laugh. And I thought it stood for Politically Correct Jim:rofl:
     
  8. WiskyT

    WiskyT Malcontent

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    First, and most importantly, Wisky is spelt wrong :whistling: on purpose because the name I wanted once upon a time was taken with the proper spelling. I had to murder the Queen's English to use the name I wanted. Just be glad I didn't pick something like 3VeRYtH1n65Uck5 like all the people under 30 do. Nothing like a screen name that people need an Enigma machine to decode.

    Second, I suggest stepping back farther for a couple of reasons. One, if your ES is 200 on a 1050fps load, it is the most likely cause of getting readings like that. Either that or you're sniffing starting fluid while you charge your cases. The second reason I suggest it is because it is cheap and easy to do.

    Put a target right behind your chrono with the bull in the sweet spot of the sensors. I put a blank cardboard behind the chrono and color in a bull right where I want it. The reason you shot your chrono is because you looked at it. At some point as you broke the shot off, you looed at the chrono and your bullet will go where you are looking. Give yourself a nice bull to look at and take your time.
     
    Last edited: Mar 14, 2010
  9. XDRoX

    XDRoX

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    Will do. Thanks guys.
     
  10. WiskyT

    WiskyT Malcontent

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    :embarassed: Uh, I just realised that XDRoX has one of those screen names. Uh, it looks good on you though!
     
  11. XDRoX

    XDRoX

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    :rofl:
    That's OK, I didn't take offense.
    BTW, I was under 30 when I made it up:supergrin:
     
  12. dudel

    dudel

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    10'-20' should be fine for a 9mm round.

    The high ES and SD you're seeing isn't related to the distance to the chrono (in this case). There is an inconsistency in your process. Same headstamp; but same number of rounds put through them? Did you weigh each projectile to control weight variance? Were the insides of the cases clean so that each projectile overcomes the same friction from the case? All these variations cause change in speed. Plus, your barrel was getting dirtier with each round fired. Some people run a boresnake after each round, others get crazier.

    You're not going to see zero ES or SD. You want to bring it down to some reasonable and consistent value, that gives you good accuracy. Handloader did a story a few months ago where the author tried to control these various variables, turned out that the load with the highest ES also had the best accuracy. So don't get too hung up on ES or SD.

    When it's all said and done, hits on target is what counts. No prizes are given for lowest ES or SD.
     
  13. GioaJack

    GioaJack Conifer Jack

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    Want words of wisdom... okay, here's some.

    If your bullets won't actually penetrate your chrony you're probably loading way too light.

    Want more...

    Don't ever, ever accumulate three ex-wives... you'd rather take a kick in the nuts with a frozen boot... trust me. :crying:

    That's all the wisdom I've accumulated in my life... sad, isn't it.

    Jack
     
  14. XDRoX

    XDRoX

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    I have no idea how many times the brass was loaded. I did not clean out the brass nor weigh the bullets. Nor did I clean the barrel. So, by my sloppy reloading process, do you think the data is valid?

    All I really wanted to know was if the rounds were going a decent speed. Not too slow or too fast. I am really just trying to come up with a plinking round that I can load 1000 of and have on hand every time I go shooting.
     
  15. XDRoX

    XDRoX

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    I already started buying two of each gun. You know, just in case of divorce and she takes half of everything:whistling:
     
  16. n2extrm

    n2extrm

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    How is the lighting above the crony? If you have poor light it will be a bear to get real numbers. I had this problem my first time out with the crony. I spent half the day trying to figure that out. The second half I had much better numbers. If the weather gets better soon I will give it another try.
     
  17. Colorado4Wheel

    Colorado4Wheel

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    How are you loading the ammo? Are you individually weighting the charges? Are you using a powder measure and just letting it do it's job. Believe it or not. I have had better results setting the Powder Measure to throw the charges and just letting it throw the charge. Individually weighting the charges, especially if you don't make sure your not distrubing various amount of built up carbon inside the case when you size and then weight is a great way to get really high Ext. Spreads. Said another way. If you size/deprime, throw a charge, weight the charge, find it's a little low or high, then adjust the amount in that charge, you are going to get high ext. spreads. Thats because your knocking carbon build up off the inside of the case and then weighting that carbon with your powder, You then adjust it up or down for no good reason. Also, I would not back up more then 20 feet. Thats should be plenty for your load. More then likely something else is going on besides your load causing the chrono to read wrong. Are you able to set the thing up in the shade? Or try a overcast day. It's something else in my opinion besides the blast from your gun. Just to be sure you can take a target, cut a 8 inch hole in the target, and shoot through the target. That will protect the sensor from any direct blast.
     
    Last edited: Mar 14, 2010
  18. XDRoX

    XDRoX

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    Thanks everyone for your input.
    C4W, I was shooting before the sun came over the mountain, so it was well lit, but no direct sunlight. I think it would be considered ideal lighting conditions. What you say about weighing carbon is very interesting. I never considered that.

    New question for everyone:
    Considering that I did not do all the proper procedures to the "T", is my data valid? In other words can I assume that the rounds I made shoot approximately 1044fps?
    All I am really trying to do is come up with a plinking round.
    Thanks
     
    Last edited: Mar 14, 2010
  19. GioaJack

    GioaJack Conifer Jack

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    To Plink...

    The recreational activity of firing a projectile with no particular goal other than for enjoyment or to overtly exercise one's Second Amendment rights.

    Equipment needed for plinking...

    One firearm and at least one bullet whose projectile travels at least as, or faster than the intended target.

    It should be noted that the above referenced definition may not be verbatim, or even close to that found in Merriam Webster's dictionary but hey, who ya gonna believe... me or a total stranger? :whistling:

    Jack
     
  20. WiskyT

    WiskyT Malcontent

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    Don't let Jack fool you, he and Miriam Webster went to the prom togeather.