Author Topic: 1st Chrono use for load development, does this look right?  (Read 1033 times)

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Offline Red Dog Leader

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Re: 1st Chrono use for load development, does this look right?
« Reply #15 on: June 09, 2018, 08:53:13 PM »
IDescribe:
“Your first obvious problem is that the numbers you reported are not correct:
915 to 1056 is an ES of 141, not 33, and your SD should be MUCH higher than 13.3
970 to 1058 is an ES of 88, not 86”



Yes, you are correct, my old eyes cant see those tiny numbers on the phone app… :o
re ran on excel when they got logged into my notes.

I will incorporate your chrono suggestions also next time.

I’ll m/t hopper after a few days if I’m loading the same rounds then moving on to other calibers….

The original load ladder was loaded middle of May. Next I was loading up .308/185 Berger’s for my F class rig and the gempro 250 was flakey, to the point I quit using it and relied on using the Hornady Auto Charge/then trickle.

Sent GP250 to myweigh to be checked, Friday got an email from Myweigh and they said scale is FUBAR, needs replacing….

So the next ladder of N320/124’s were Lee dippered and then trickled…Hopefully my #'s will be better....

When plated run out will look at MG or PD bullets....
Thanks for the help IDescribe

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Offline tdogg

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Re: 1st Chrono use for load development, does this look right?
« Reply #16 on: June 09, 2018, 10:12:09 PM »
How long have you had the gem pro?   Just curious as I have one that is pushing 5 yrs I think?

Cheers,
Toby

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Offline Red Dog Leader

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Re: 1st Chrono use for load development, does this look right?
« Reply #17 on: June 09, 2018, 10:57:09 PM »
How long have you had the gem pro?   Just curious as I have one that is pushing 5 yrs I think?

Cheers,
Toby

Sent from my SM-G950U using Tapatalk

10 Months,
From Gempro:

"We are sorry to hear that your GemPro scale is not functioning properly. Unfortunately, we are experiencing performance issues with the GemPro scales we have in stock.  Because we cannot guarantee satisfactory performance with the GemPro line at this time and do not have another replacement option, we would like to refund your purchase by sending you a prepaid debit card in the amount of your original purchase.'       



that debit card is going into the piggybank for a A&D FX120

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Offline tdogg

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Re: 1st Chrono use for load development, does this look right?
« Reply #18 on: June 10, 2018, 09:46:13 AM »
Bummer about the gempro situation.   I've heard good things about the A&D scales.   

Cheers,
Toby

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Offline IDescribe

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Re: 1st Chrono use for load development, does this look right?
« Reply #19 on: June 10, 2018, 05:40:09 PM »
Buy a Dillon scale.  You shouldn't be measuring charges often enough for the minor convenience of an electronic to mean much, and the beam scale is more consistent.  My Dillon beam scale steadies very quickly.
« Last Edit: June 11, 2018, 04:27:27 AM by IDescribe »

Offline Wobbly

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Re: 1st Chrono use for load development, does this look right?
« Reply #20 on: June 10, 2018, 10:05:13 PM »
Buy a Dillon scale.  You shouldn't be measuring charges often enough for the minor convenience to mean much, and the beam scale is more consistent.

The Dillon Eliminator is made for them by Ohaus. It's the same scale as the older RCBS 505, which is no longer available I understand.

A good beam scale is consistent over decades. And these high-end Ohaus units are everything the Lee is not. Trust me on this.
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Offline RegionRat

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Re: 1st Chrono use for load development, does this look right?
« Reply #21 on: June 11, 2018, 04:06:28 AM »
Just another two cents...

If you are worried about trusting the uncertainty of your charges, invest in some check weights.
If you are worried about trusting your velocity performance, invest in some check ammo. For example some known match grade 9mm 124. It doesn’t have to be identical to yours, but close enough. Think along the lines of Atlanta Arms or similar known good ammo.

The check weights form a reference for the gain and repeatability on your scale.

The reference ammo helps debug your reloading process, your gun, and your chrono technique.
The same applies to rifle work. It helps to have a fallback position when there is confusion in complex issues, if you have known ammo performance to check things that are standardized.

Good Luck.

Offline Wobbly

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Re: 1st Chrono use for load development, does this look right?
« Reply #22 on: June 11, 2018, 07:42:04 AM »
If you are worried about trusting the uncertainty of your charges, invest in some check weights.


Great point. Digital scales work by measuring the difference in electrical resistance of a membrane that is stretched when a load is added to the scale. Therefore, everything that can effect resistance readings (temperature, drafts, power stability, electrical fields, solder joints, voltage levels, software reliability, mechanism lubrication, etc) will affect the number the scale flashes up on the screen.

You'll notice that all those influences are things you cannot see, hear, touch, or feel. In other words, if your readings are incorrect you have NO indications that things are going wrong.

Additionally, becasue the digital scale works the way it does it can be "on the money" at the "zero" point and at the same time be way off at other measurements. The cartoon below tries to depict that....



In the cartoon the digital scale was correctly "zeroed" at 20 grams using the supplied check weight. Unfortunately, 20 grams equals 308.6 grains and you might be working with pistol loads in the 5 grain arena. So becasue of a sticky mechanism the readings (red line) are high in the 5 grain range. And still, because of low voltage the readings are low in others. Yet at 20 grams it's perfect !

So the point is, with a digital scale you must zero with check weights in the range you intend to work. That's the only way to be fairly sure the readout is fairly accurate.
« Last Edit: June 13, 2018, 05:21:45 PM by Wobbly »
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Offline 1SOW

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Re: 1st Chrono use for load development, does this look right?
« Reply #23 on: June 11, 2018, 12:33:34 PM »
I made a check weight out of a  coil of stainless steel weighing  exactly 4.5 grs to be in my load ranges for 9mm.
I don't load for rifles, so I didn't need the heavier check weights.  This check weight agrees with my Dillon and Lee beam scale perfectly, and It simplifies Zeroing the scale nicely.   I never use the Lee scale.
« Last Edit: June 12, 2018, 12:17:29 AM by 1SOW »

Offline Red Dog Leader

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2nd Chrono use for load development, redux.....
« Reply #24 on: June 13, 2018, 05:12:18 PM »
Re did the load ladders
Used Lee scale to dial in 10 drop AVG's on progressive Used certified weights to check 1 gram...smallest I have....
10 rounds per string
Made a stand for a clip on umbrella, mostly sunny....

Much better results. Well tighter than before....still learning....

3.9 = AVG 993.6 SD 13.39 ES 44
4.0 = AVG 1036 SD 11.4  ES 36
4.1 = AVG 1050 SD 12.48 ES 38
4.2 = AVG 1069 SD 5.74   ES 19

I HOPE I READ THIS OFF THE CELL APP CORRECT...  :o

https://www.amazon.com/photos/share/3jdgrztsFVL4PkSumUcWj0gwjPHMKlc3aJfA9MeEYRN

Again, really appreciate the suggestions & tips...Red

PS quick load says I could get to 4.3, "warning near Max" think its worth it...that 4.2 was pretty tight group of rest...
« Last Edit: June 13, 2018, 05:18:49 PM by Red Dog Leader »
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Offline 1SOW

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Re: 1st Chrono use for load development, does this look right?
« Reply #25 on: June 14, 2018, 08:24:37 PM »
That chrono alignment looks good. 

Offline Wobbly

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Re: 2nd Chrono use for load development, redux.....
« Reply #26 on: June 15, 2018, 08:06:54 AM »
Re-did the load ladders. Used Lee scale to dial in 10 drop AVG's on progressive. Used certified weights to check 1 gram... smallest I have....
• Used a Lee balance beam scale ? Balance beam scales differ in that if they are "off", then they vary by a constant percentage. That is to say, if they are "off" by +1/2% at 3gr, then they are off by the same +1/2% at 200gr. In my cartoon of scale accuracy, that is represented by the green line. So "constant percentage" of variation plots as a straight line. That's "constant", as in "forever". And that's forever as in Mt. Mckinley not moving to GA, God's promises, or the sun coming up in the morning.... however you want to envision it. The only sources of variation in the balance beam are the friction at the point of teeter-totter, the accuracy of the notch spacing on the beam, and the variation of Gravity. 

• 1 gram = 15.4 grains, which is not close enough to your 4 to 5 grain measurement arena to use on a digital scale. If you wanted that, then RCBS and others make check weights in that range. Search MidwayUSA for said check weights.



3.9 = AVG 993.6 SD 13.39 ES 44
4.0 = AVG 1036 SD 11.4  ES 36
4.1 = AVG 1050 SD 12.48 ES 38
4.2 = AVG 1069 SD 5.74   ES 19
These numbers look excellent. Good work.


PS quick load says I could get to 4.3, "warning near Max" think its worth it...that 4.2 was pretty tight group of rest...
Quick Loads is software that is making estimates, not measurements. Don't confuse the two ! Yes, you are near Max Load, but the proof is in the actual velocity measurement given by the chrono.

What saves you with 9mm is that, unlike some calibers, there is 9mm+P which works at higher pressures and higher velocities. So it's OK for your testing in a modern 9mm pistol to creep past Max Load velocities, just don't make a habit of it. You do that by watching your velocities, which is the entire reason to own a chrono. Hope that make sense.


Everything we do in reloading is to keep the chamber pressures under control. Think about it... we use accurate scales and accurate powder measures. We seat the bullets with accurate seating dies. Then we measure the velocities with an accurate chrono. It's all so the results are highly repeatable. Which is another way of saying "safe to shoot".

 ;)
« Last Edit: June 15, 2018, 08:16:22 AM by Wobbly »
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Offline Red Dog Leader

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Re: 2nd Chrono use for load development, redux.....
« Reply #27 on: June 16, 2018, 11:25:10 PM »
Quote
Quick Loads is software that is making estimates, not measurements. Don't confuse the two ! Yes, you are near Max Load, but the proof is in the actual velocity measurement given by the chrono.

What saves you with 9mm is that, unlike some calibers, there is 9mm+P which works at higher pressures and higher velocities. So it's OK for your testing in a modern 9mm pistol to creep past Max Load velocities, just don't make a habit of it. You do that by watching your velocities, which is the entire reason to own a chrono. Hope that make sense.


Everything we do in reloading is to keep the chamber pressures under control. Think about it... we use accurate scales and accurate powder measures. We seat the bullets with accurate seating dies. Then we measure the velocities with an accurate chrono. It's all so the results are highly repeatable. Which is another way of saying "safe to shoot".

 ;)

Thanks Wobbly, will keep it in mind.



[Mods corrected quote]
« Last Edit: June 18, 2018, 12:00:17 AM by Wobbly »
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anything