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Will have new chrono tomorrow - help!


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Thanks to all for the encouragement to buy a chrono! A suggestion I was given was the Competition Electronics ProChrono Digital Chronograph (thanks Memphis!) It seems to have good reviews and is only $100 AND I will probably kill it anyway...

After reviewing posts regarding chronos I now realize they provide more than just validating projectile speed... I'd like to be able to utilize it to it's fullest capabilities and any articles/links/suggestions that would help me learn how to use it correctly to begin with would be most appreciated!

Thanks in advance from IGG.

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It's a pretty basic tool. The buttons are easy to figure out, even for me.

 Put a battery in it, turn it on, shoot 10 rounds through it from about 10ft away at about 1 shot per second.

Hit the review button and it will show each round. I just fast forward through the 10 shots until it reads HI, then LO, then AVG, then ES, and finally SD. Then I just use a calculator to multiply bullet weight X AVG for PF.

I personally only worry about AVG and SD as I know my reloading process is solid and I rarely get odd readings that are my fault.

Each shot you shoot will show the velocity so if you shoot slow you can verify each shot appears to be in the ball park.

Keep a fresh spare battery handy as a weak battery is the first thing I check when readings get wonky.

I put some Velcro on the sky screens and an old plastic real estate sign and always use it with this "HOOD" in place. The worst readings can come under clear blue skies so the white shade maker eliminates that. Also avoid using it early or late in the day when bright sun is lower than the hood. Readings go haywire then sometimes as well.

i like to put a target down range at about 20 yards with a black spot for an aiming point. This helps keep you from shooting the chrono and it tells you how accurate each tested load is.

 Other than that, just get a cheap tripod and go for it.

 

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One suggestion that has saved me several times was substituting wooden dowel rods for the steel ones included with the chrono. If you shoot the rods, which is a distinct possibility and almost guaranteed over time, you will only destroy a wooden dowel instead of hitting a steel rod and maybe causing more damage. You can get a bunch of them real cheap at any big box store. Mine were slightly too thick initially but a few minutes with some sandpaper on each end got them fitting fine.

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That little digital link blue-tooth adapter is pretty cool and lets you save your load data and results in electronic files.  It does all the math for you and even will provide graphing if you want.  Something to think about for down the road. 

Personally, I look at the chrono as a invaluable reloading tool...as important as a good scale.  Glad you got a good one!

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1 hour ago, Sarge said:

It's a pretty basic tool. The buttons are easy to figure out, even for me.

 Put a battery in it, turn it on, shoot 10 rounds through it from about 10ft away at about 1 shot per second.

Hit the review button and it will show each round. I just fast forward through the 10 shots until it reads HI, then LO, then AVG, then ES, and finally SD. Then I just use a calculator to multiply bullet weight X AVG for PF.

I personally only worry about AVG and SD as I know my reloading process is solid and I rarely get odd readings that are my fault.

Each shot you shoot will show the velocity so if you shoot slow you can verify each shot appears to be in the ball park.

Keep a fresh spare battery handy as a weak battery is the first thing I check when readings get wonky.

I put some Velcro on the sky screens and an old plastic real estate sign and always use it with this "HOOD" in place. The worst readings can come under clear blue skies so the white shade maker eliminates that. Also avoid using it early or late in the day when bright sun is lower than the hood. Readings go haywire then sometimes as well.

i like to put a target down range at about 20 yards with a black spot for an aiming point. This helps keep you from shooting the chrono and it tells you how accurate each tested load is.

 Other than that, just get a cheap tripod and go for it.

 

Thanks Sarge, how do I understand SD & ES and how to benefit from that data?

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1 hour ago, DougM said:

One suggestion that has saved me several times was substituting wooden dowel rods for the steel ones included with the chrono. If you shoot the rods, which is a distinct possibility and almost guaranteed over time, you will only destroy a wooden dowel instead of hitting a steel rod and maybe causing more damage. You can get a bunch of them real cheap at any big box store. Mine were slightly too thick initially but a few minutes with some sandpaper on each end got them fitting fine.

Sounds like you might have learned from experience, and that is a great idea - thx!

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1 hour ago, Bamboo said:

That little digital link blue-tooth adapter is pretty cool and lets you save your load data and results in electronic files.  It does all the math for you and even will provide graphing if you want.  Something to think about for down the road. 

Personally, I look at the chrono as a invaluable reloading tool...as important as a good scale.  Glad you got a good one!

Thanks Bamboo, I will keep that in mind as I like working with data and graphs, etc. Memphis is the one who recommended what I ordered, kudos to him!

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the lowest you can get for both imo.  I only really look at SD.  If I get into the single digits it means (to me) that the ten shot ladder was run very consistently through my 650XL...that the handle pull was consistent to allow a very small range of powder drop variation.

If my SD is high, I look at the speed of all ten to see if I have a nonconforming speed relative to the others.  One that is +/- 75fps (even 30 or 40) from "the group" can make an inaccurate SD.

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22 hours ago, amada8 said:

the lowest you can get for both imo.  I only really look at SD.  If I get into the single digits it means (to me) that the ten shot ladder was run very consistently through my 650XL...that the handle pull was consistent to allow a very small range of powder drop variation.

If my SD is high, I look at the speed of all ten to see if I have a nonconforming speed relative to the others.  One that is +/- 75fps (even 30 or 40) from "the group" can make an inaccurate SD.

 

Guess what I found in my driveway last night?

Hypothetically if I find my average velocity is say 900 to pick a number and the SD shows single digits as you mentioned  I should be quite pleased right?

So if I had a high SD I would also have a high ES? And if I corrected a high SD the high ES would also correct?

Also Some say shoot 10 others say at least 20 per string..?

And if I have a high ES and determine it was one or a couple that are 30/40/75 out the only fix is being more careful while pulling the handle on my 650..?

CE Chrono.jpg

Edited by IGOTGLOCKED
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Also fyi if you didn't know --- I spoke to the manufacturers and they said whatever happens to the chrono (even if I kill it!) a repair would be a minimum of $15 and a max of $60 depending upon what it takes to repair it! Thought that was pretty awesome! Really nice folks there, very patient and proud of what they do...

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1 minute ago, IGOTGLOCKED said:

 

Guess what I found in my driveway last night?

Hypothetically if I find my average velocity is say 900 to pick a number and the SD shows single digits as you mentioned  I should be quite pleased right?

AS LONG AS IT'S ACCURATE.

Also Some say shoot 10 others say at least 20 per string..?

I SHOOT STRINGS OF 10 TO KEEP THINGS SIMPLE BUT WILL SOMETIMES SHOOT HUNDREDS OF ROUNDS IN TOTAL TO GET GOOD SOLID DATA.

CE Chrono.jpg

 

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3 minutes ago, broadus123 said:

I love mine. Bought it a few yrs ago. Had trouble with my chrony. I have found that the readings are the same as the readings I get at matches. The chrony readings were a little higher.

Awesome, thanks for the vote of confidence!

 

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ES is extreme spread.

Ideally every single one of your rounds would be the exact same velocity. However that's something you'll never see. Extreme Spread is the difference in FPS of your fastest bullet minus your slowest one. Pretty simple stuff.

SD is standard deviation. Statistically, how far off from the mean each of your rounds is going to be. An SD of 5 would be some incredibly consistent "match grade" ammo, and anything under 10 is ideal.

On the other hand, I haven't been able to work up a load with Ramshot Competition powder in 9mm that is lower than 22. They're all over the place velocity-wise. Accordingly, RS Comp is being burned up in my practice ammo now.

(Side note. That ammo is still accurate as hell, grouping around 2inches at 25yd!)

As mentioned above, you'll want to see *why* your ammo has the variation that it does. For example, if you have fired 18 rounds over the chrono that are all 955 to 970 fps but round #19 clocks at 859 and ruins your ES... It's likely that either the chrono read it wrong, or some of the powder slopped out of the case while it was on the press. That's not a huge cause for concern. It happens.

However, if your rounds are varying wildly by 100fps (970, 901, 1002, 940, 995, 911 would be example readings for each shot) then you'd want to look for a cause somewhere in your reloading process. Change powders and see if your powder measure just doesn't like whatever you used, for example.

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And also agreeing with the others...

a larger group of shots is more accurate, statistically. Would you pay attention to a poll predicting who was going to win an election if they only talked to three people? ;)

There's a point where it isn't worth the time, though. If I run 10 rounds across a chrono and every single one is 133-35 power factor and the ammo shoots tight groups through my gun? 

I'm gonna leave ballistic-engineer mode, call it good, and spend the rest of my range time getting better at shooting fast and all the other USPSA skills I need to hone.

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17 minutes ago, MemphisMechanic said:

ES is extreme spread.

Ideally every single one of your rounds would be the exact same velocity. However that's something you'll never see. Extreme Spread is the difference in FPS of your fastest bullet minus your slowest one. Pretty simple stuff.

SD is standard deviation. Statistically, how far off from the mean each of your rounds is going to be. An SD of 5 would be some incredibly consistent "match grade" ammo, and anything under 10 is ideal.

On the other hand, I haven't been able to work up a load with Ramshot Competition powder in 9mm that is lower than 22. They're all over the place velocity-wise. Accordingly, RS Comp is being burned up in my practice ammo now.

(Side note. That ammo is still accurate as hell, grouping around 2inches at 25yd!)

As mentioned above, you'll want to see *why* your ammo has the variation that it does. For example, if you have fired 18 rounds over the chrono that are all 955 to 970 fps but round #19 clocks at 859 and ruins your ES... It's likely that either the chrono read it wrong, or some of the powder slopped out of the case while it was on the press. That's not a huge cause for concern. It happens.

However, if your rounds are varying wildly by 100fps (970, 901, 1002, 940, 995, 911 would be example readings for each shot) then you'd want to look for a cause somewhere in your reloading process. Change powders and see if your powder measure just doesn't like whatever you used, for example.

Thanks Mechanic! I actually understood everything you said - much appreciated...

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15 minutes ago, MemphisMechanic said:

And also agreeing with the others...

a larger group of shots is more accurate, statistically. Would you pay attention to a poll predicting who was going to win an election if they only talked to three people? ;)

There's a point where it isn't worth the time, though. If I run 10 rounds across a chrono and every single one is 133-35 power factor and the ammo shoots tight groups through my gun? 

I'm gonna leave ballistic-engineer mode, call it good, and spend the rest of my range time getting better at shooting fast and all the other USPSA skills I need to hone.

Ditto brother!

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