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Thread: Chronograph purpose

  1. #1
    Rainwatcher Jammer Six's Avatar
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    Default Chronograph purpose

    Okay, a beginner's question.

    Why would I care how fast a load goes, other than making power factor?

    I don't play any of the gun games, I never have to make "power factors".

    So why would I care about velocity?

    If it hits the target, it hits the target, and if it doesn't, it doesn't.

    In either case, what good is knowing how fast it hits the target?

    What would I change in a load that doesn't hit the target, based on knowing the velocity?
    "When I have your wounded."
    -Major Charles L. Kelly, callsign "Dustoff", refusing an order to leave a hot L.Z., July 1, 1964, moments before being killed by a single shot.

  2. #2
    Buff Canuck44's Avatar
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    A Chrono gives you much more than just velocity. Once you shoot a string of say 10 rds you can calculate the Extreme Spread between the highest and lowest velocities within the string and also the Statndard Deviation. What I try to do with my handgun loadings is develop a load that first makes Power Factor for shooting the games but then to find a load that results in the lowest ES and SD. Both are an indication of the likelihood of maximizing the accuracy of the pistol you are shooting. Different powders react differently to low and high charges in the different calibers, some are better for light loads while others tend to favour hotter loadings. This is also true of different handguns. So to bullets.

    If making a bang with your handgun or rifle is all that you want to achieve and maximizing the accuracy potential of your firearm is of no interst than you probably don't need a Chrono. Load them up and let fly. If on the other hand you are interested in developing loads that work especailly well in your guns then a Chrono is worth buying.

    Take Care Eh

    Bob

  3. #3
    Rainwatcher Jammer Six's Avatar
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    Default

    Okay, how do you know what to change?

    For instance, I load a load, and shoot it.

    The extreme spread and the standard deviation are bad- what do I do?

    What do I do if the load doesn't hit the target?
    "When I have your wounded."
    -Major Charles L. Kelly, callsign "Dustoff", refusing an order to leave a hot L.Z., July 1, 1964, moments before being killed by a single shot.

  4. #4
    Buff Canuck44's Avatar
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    "The extreme spread and the standard deviation are bad- what do I do?"

    Move up or down with the powder charge is my first step. Check with other shooters to see what they are achieving out of their guns. Adjust OAL of cartridges. Switch powders. Check reloading manuals. To name a few options.

    "What do I do if the load doesn't hit the target?"

    If shooting handguns:

    1. Move target to 10 yards and set sights if adjustable.

    2. Use a rest to remove variables.

    If a rifle move target to 25 yards and adjust sights. Use a rest.

    Not sure what else I can say at this point. What problems are you incurring or are you just enquiring as to why we use a Chrono.

    Take Care Eh

    Bob

  5. #5
    Rainwatcher Jammer Six's Avatar
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    I'm trying to figure how to use the information a chronograph delivers so I can decide whether or not to buy one.
    "When I have your wounded."
    -Major Charles L. Kelly, callsign "Dustoff", refusing an order to leave a hot L.Z., July 1, 1964, moments before being killed by a single shot.

  6. #6
    Dogs Like Him versifier's Avatar
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    Default

    Learning your load's Average Velocity and SD, helps you determine the efficiency of that load in your particular firearm. But there is more to the story. If you are shooting handloads in a handgun or a rifle, knowing the speed of your loads lets you figure the bullet drop at various ranges with a ballistic table. Many bullet makers provide this data at various velocities in their particular manuals, also the downrange velocities and retained energy figures, too. If you're sighted in for 100, it's nice to know how low it will hit at 150, 200, 250, 300, etc. yards so that you can either correct with the graduations in your scope reticle or adjust sights manually the correct amount. Knowing the trajectory of your loads is essential for accurate shooting at longer distances, and learning the practical value and use of the tables can save you a lot of testing at intermediate ranges, or worse, missed shots as distances change on live quarry. If you wanted to do it the hard way, you could shoot many groups at each incremental range, measuring the incremental changes in Point Of Impact at each distance, and then use that data to calculate the velocity relative at each distance based on the measured bullet drop. It's easier to simply check your muzzle velocity on your most accurate loads and look it up in the loading manual. And for that you need a chrono. It doesn't mean you need to buy yourself a top-of-the-line unit with all the bells and whistles, the pizeo chamber pressure sensors, it's own computer, printer, and lcd readout that spits out your numbers all calculated for anything you could possibly be interested, (and probably seats your primers, and polishes your brass, too, for all I know, I can't afford one) at the mere price of a small single family home. There are reliable and reasonably priced chronos on the market that are easy to use and understand: readout shot by shot of velocity and possibly remember and compare a string of several shots so you can figure out what's up with your handloads without selling off any children to pay for it. You can keep it Lee Loader simple and just shoot, or you can explore it as little or as much as you like all the way up the level of the physicist if that's what floats your boat. I just like to know where the bullet is going to hit if I have to take a long shot at a deer, or the person for whom I loaded it wants to know.
    "Stand your ground.
    Do not fire unless fired upon.
    But if they mean to have a war let it begin here."
    - Capt. Parker, Lexington Militia, April 19, 1775

  7. #7
    Buff Canuck44's Avatar
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    Default Jammer Six

    Take a look at the Chrony line of chronos. They have an entry model, the one I have, and go up from there. They all work well and are reasonably priced. versifier filled in the blanks.

    A Chrono allows yoou to go to the next step in reloading and one I think is worth while. Probably won't use it all the time but it sure helps in developing loads.

    Take Care

    Bob

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Abbreviations used in Reloading

BP Bronze Point IMR Improved Military Rifle PTD Pointed
BR Bench Rest M Magnum RN Round Nose
BT Boat Tail PL Power-Lokt SP Soft Point
C Compressed Charge PR Primer SPCL Soft Point "Core-Lokt"
HP Hollow Point PSPCL Pointed Soft Point "Core Lokt" C.O.L. Cartridge Overall Length
PSP Pointed Soft Point Spz Spitzer Point SBT Spitzer Boat Tail
LRN Lead Round Nose LWC Lead Wad Cutter LSWC Lead Semi Wad Cutter
GC Gas Check        

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