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Old 06-02-2020, 05:33 PM
Allen in MT
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Center-x spread



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All my Center-x is the same lot number and shooting it thru 2 different rifles with a chronograph 4 groups of 5 the spread for each 5 round group was between 20 and 36fps difference.
The spreads was 1015 to 1051,,&,1035 to 1050
and the other rifle was 1030 to 1060,, & 1040 to 1060
Seem like a pretty big spread for center-x.
thoughts?
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  #2  
Old 06-02-2020, 06:04 PM
Squeezer
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Quote:
Originally Posted by Allen in MT View Post
All my Center-x is the same lot number and shooting it thru 2 different rifles with a chronograph 4 groups of 5 the spread for each 5 round group was between 20 and 36fps difference.
The spreads was 1015 to 1051,,&,1035 to 1050
and the other rifle was 1030 to 1060,, & 1040 to 1060
Seem like a pretty big spread for center-x.
thoughts?
Those are better results than I have gotten, although my testing sample size is larger. I have tested one lot (26650 512981) of CenterX through my Three CZ455's (boxes of 50) with the following results:

Varmint (20.9")
Muzzle velocity 1,045 fps
Extreme Spread 51.00 fps
Standard deviation 12.15 fps

Training Rifle (24.8")
MV 1,051
ES 60.00
SD 10.30

UltraLux (28.66")
MV 1,006
ES 39.00
SD 8.54
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  #3  
Old 06-02-2020, 06:18 PM
Hi-NV Shooter
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Quote:
Originally Posted by Allen in MT View Post
All my Center-x is the same lot number and shooting it thru 2 different rifles with a chronograph 4 groups of 5 the spread for each 5 round group was between 20 and 36fps difference.
The spreads was 1015 to 1051,,&,1035 to 1050
and the other rifle was 1030 to 1060,, & 1040 to 1060
Seem like a pretty big spread for center-x.
thoughts?
Bottom line how did that relate to performance on paper? did both rifles shoot good with it?

Lee
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  #4  
Old 06-02-2020, 06:45 PM
Allen in MT
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Originally Posted by Hi-NV Shooter View Post
Bottom line how did that relate to performance on paper? did both rifles shoot good with it?

Lee
Shot pretty decent for these 71 year old eyes I thought. The velocity wasn't close to what Lapua claims of 1073 for center-x
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  #5  
Old 06-02-2020, 06:46 PM
jaia
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I've had some extremely good boxes of CenterX that held less than 40 fps ES for 50 shots.
I've also had boxes that spit hot fliers pushing the ES to more than 60 fps for 50.
The boxes are labeled with the expected average velocity, but due to production variations
most likely will be a bit higher or lower, even within the same lot. It's rimfire, quality is not a constant.
Some lots are decent, some aren't.
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  #6  
Old 06-02-2020, 10:11 PM
Straightshooter1
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Quote:
Originally Posted by Allen in MT View Post
All my Center-x is the same lot number and shooting it thru 2 different rifles with a chronograph 4 groups of 5 the spread for each 5 round group was between 20 and 36fps difference.
The spreads was 1015 to 1051,,&,1035 to 1050
and the other rifle was 1030 to 1060,, & 1040 to 1060
Seem like a pretty big spread for center-x.
thoughts?
My average ES for 10 round sets (over a total of 150 rounds) has been 22 fps with the lot of Center-X that I have. The lowest ES was 10 and the highest was 36. Since lots can vary, I'm sure some are likely to do better and some worse.

Average velocity for those 150 rounds was 1100 fps (that's not a rounded number) out of my 18" Shaw match barrel, using a MagnetoSpeed v3 chrono.

It's shoots pretty good for me with 73 yr old eyes requiring tri-focals.

Last edited by Straightshooter1; 06-02-2020 at 10:18 PM.
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  #7  
Old 06-05-2020, 01:30 PM
Jory45acp is online now
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What was the barrel condition when you started measuring? Was it just cleaned, have older ammo residue present, seasoned with Center-X 20rds before measuring started? Also in your group measurement where was high and low point. Was they at opposite ends of the group which might explain why or randomly placed in the order fired. I've learned careful data tracking is often key to explaining these variations. And yes it can often times take you into the weeds of getting seriously technical. I myself learned these things from watching how Olympic teams pic ammo through testing from years ago. The data and comparison to show what was happening when allowed them to almost get freaky in predicting when a ammo would begin to open a group up. Anyways just a couple points to think about in figuring out what is happening with your spread.
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