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Load all over the place


Chrisyoung

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I've started developing a new load with sport pistol. 125 gr blue bullets 1.125 col with 3.9 gr of sport pistol and I got some extreme spreads in velocity and I'm have trouble figuring out if it's a load problem of chrono problem anyone seen anything like this before? Any insight would be greatly appreciated. All test was done with a glock 19 gen4 stock barrel 

20190322_161845.jpg

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1 minute ago, DKorn said:

First thing to check- how confident are you in your numbers? In other words, how consistent are your powder charges and overall lengths? 

Col are withing 0.005 from shortest to longest I dont think it's the col.  I set powder drop to 3.9 then averaged it out over 10 drops and got 3.93. I'll check and make sure each individual powder drop is accurate thanks. 

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Sport Pistol has been very, very consistent for me.  It meters very well on my Dillon.

Is the powder clumped possibly or there's debris interfering with the powder drop?  From what you indicate the answer is no.

When I come back to reload when it's been a day or two I take the primer follower and poke/stab/churn the powder in the measure so nothing is sticking together & tap the measure with the wrench.  Then do the drops of 10 three times to make sure all is stable before reloading.  Sport Pistol has always been spot on.

 

Only other thing I can think of to produce such horrendous spreads is how far from the chrono are you?  If it's too close the blast, smoke, etc can possibly be interfering. 

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4 minutes ago, BJB said:

Sport Pistol has been very, very consistent for me.  It meters very well on my Dillon.

Is the powder clumped possibly or there's debris interfering with the powder drop?  From what you indicate the answer is no.

When I come back to reload when it's been a day or two I take the primer follower and poke/stab/churn the powder in the measure so nothing is sticking together & tap the measure with the wrench.  Then do the drops of 10 three times to make sure all is stable before reloading.  Sport Pistol has always been spot on.

 

Only other thing I can think of to produce such horrendous spreads is how far from the chrono are you?  If it's too close the blast, smoke, etc can possibly be interfering. 

I move the chrono around a few time from 10 feet out to 25 feet or so with the same result even tried the battery out of my shot timer in the chrono think the battery was weak. I will at this is the frist time in about 6 months that I've use my chrono. 

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19 minutes ago, fatjoe123111 said:

I guess the other question is how confident are you that your chrono is right?  Also if you shot on a sunny day the chrono can give you some wrong numbers. 

I haven't thought about the sunlight affecting the reading it was a bright day today. 

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Depending on the bullet, i have absolutely gotten radically different numbers in direct sun versus shade. Notice how at most matches the chrono  is out of the sun? It's not to keep the dudes working it from getting a sunburn.

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I had a similar issue and a larger dia.bullet solved the problem. It could be bad readings from the chrono but if your bullet is not fitting your barrel good you could have some gas blowing by the bullet causing the bad numbers.

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3 hours ago, IronicTwitch said:

I've seen erratic Chrono results when sunlight plays on the sensors. Try to use another target to keep the sensors in the shade? 

^^^

This.

 

My Caldwell hates bright sun, even with the shades mounted it has to be in the shade for consistent results.

 

I found SP to be as consistent as TG in my loads. 

 

 

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If I don’t shoot right over the sensors of the chrono I get similar erratic results. Also distance from the chrono play a role.
Finally, if you have the competition electronics deluxe chrono with built in Bluetooth, it has a quirk when recording duplicate velocities. When you have the same velocity in 2 or more consecutive shots, if the string in the chrono is full, it does not record the subsequent velocities to your phone.


Sent from my iPhone using Tapatalk

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26 minutes ago, blue_dot_glock said:

i'm working up summers 0.357" 125g hi-tek at 1.120" in my G19gen4 and had some pretty good results this weekend:

 

 

g19_20190319.PNG

That's great results! I'm going to try mine again in a few days when the suns not out. 

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43 minutes ago, Chrisyoung said:

That's great results! I'm going to try mine again in a few days when the suns not out. 

thanks! i bought a caldwell g2 chronograph because the bullet passes under the sensor, lights pointing up. no worries so far about the sun; i don't know if it works under florescent lights, as none of the indoor ranges around here allow chronographs.

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OP,

 

Are you sure your not getting bullet set back from the round chambering? 

 

Probably not but if you run down everything else and still are getting the spread, check that. 

 

 

 

 

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I have a ProChrono Digital and a Caldwell Pro kit.  Neither one will give good results if sunlight touches any port.  I learned decades ago the chrono must be in the shade with the screens exposed to the sky.  Lately, I just use the IR screens that came with the Caldwell.  However, I use them on the ProChrono, because that is the more accurate device.

 

25 yards is too far to chrono.  You get your most accurate results when the bullet travels a path down the centerline of the chrono and parallel to the sensors.  Any deviation from this path decreases the reported velocity, because the path across the sensors was longer.  10' is the longest I chrono at.  If you are shooting an Open gun, you can get away with 5'.  Just subtract 5-6 fps to get the 10' reading.

 

Bullet setback can absolutely cause wild readings like that.  My major Limited load was 1.126" to work in my CZ TS.  I got great, consistent chrono results.  My 2011 also fed bullets at that OAL so I used them.  I could feel they were inconsistent just by shooting them.  I chrono'd them.  Awful.  The reason was inconsistent setback with mixed range brass.  I loaded to 1.180" for the 2011 and the problem disappeared.  I was back to single digit SDs.  

Edited by zzt
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1 hour ago, zzt said:

I have a ProChrono Digital and a Caldwell Pro kit.  Neither one will give good results if sunlight touches any port.  I learned decades ago the chrono must be in the shade with the screens exposed to the sky.  Lately, I just use the IR screens that came with the Caldwell.  However, I use them on the ProChrono, because that is the more accurate device.

 

25 yards is too far to chrono.  You get your most accurate results when the bullet travels a path down the centerline of the chrono and parallel to the sensors.  Any deviation from this path decreases the reported velocity, because the path across the sensors was longer.  10' is the longest I chrono at.  If you are shooting an Open gun, you can get away with 5'.  Just subtract 5-6 fps to get the 10' reading.

 

Bullet setback can absolutely cause wild readings like that.  My major Limited load was 1.126" to work in my CZ TS.  I got great, consistent chrono results.  My 2011 also fed bullets at that OAL so I used them.  I could feel they were inconsistent just by shooting them.  I chrono'd them.  Awful.  The reason was inconsistent setback with mixed range brass.  I loaded to 1.180" for the 2011 and the problem disappeared.  I was back to single digit SDs.  

I just put a target with white side down on top of the screens on my pro chrono digital. makes it's own shade. Only time mine ever got erratic was because the 9V battery was weak.

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