Primer pocket difference in velocity, ES SD.

[viking78]

I have had a long time wish to test, does the small primer pocket has anything better, than large rifle primer in Lapua brass and
popular 6.5 Creedmoor caliber.
Received finally the LR brass from Lapua to test it.
Competition Electronics DLX chrono was the measuring tool, i like it better than labradar, it will work, no matter how you shoot thru it.
I have read a document few year back in G&A, and there the sr primer pocket was better.
I had 123gr Scenar and Vihtavuori N150 38,6gr in both cases, both cases were brand new, none shot.
SR is CCI magnum 450, and LR CCI 200.
Check out the results.

 

[spife7980]

You can’t just tell us? We have to watch a YouTube to pretend we are interested?

 

[918v]

He say large primer pocket better es and sd.

 

[Doom]

I waiting on his analysis of his data. I would love for him to publish his data!

 

[918v]

I know that when I tried small primer brass with 450s and Staball in my 6.5 the ES was horrible.

 

[DeathBeforeDismount]

I know that when I tried small primer brass with 450s and Staball in my 6.5 the ES was horrible.

Don't use shit powder and won't have problems.

3.5 SD with H4350 or Varget and 450s.

 

[acudaowner]

have had good results with both small primer pocketed brass as well as large primer pocketed brass expensive brass like Peterson , and lapua , and alpha to the cheap crap like snb and what I have the most of federal large pocketed brass depending on the load and what powder I was running at that time . numbers as low as 2.2 and as high at 59.something ( hoping never to see that again it sucked ). from cheap primers like standard federal and Remington and Winchester ( not a big fan of them so far getting a lot of hang fires ) . To the expensive match and br2 and 4's again depending on the powder and load they have all produced extreamly good numbers , and groups as well as bad numbers and while I blame my self for any bad groups it no doubt could be a bit of both me and the primer .

 

[Baron23]

I have had a long time wish to test, does the small primer pocket has anything better, than large rifle primer in Lapua brass and
popular 6.5 Creedmoor caliber.
Received finally the LR brass from Lapua to test it.
Competition Electronics DLX chrono was the measuring tool, i like it better than labradar, it will work, no matter how you shoot thru it.
I have read a document few year back in G&A, and there the sr primer pocket was better.
I had 123gr Scenar and Vihtavuori N150 38,6gr in both cases, both cases were brand new, none shot.
SR is CCI magnum 450, and LR CCI 200.
Check out the results.

Thank you for posting this and I get a kick out of seeing you in short sleeves after watching vids of you and Roni shooting...above the arctic circle! haha ;-)

Just thought....and there have been lots of threads on this with much heated debate....but the statisticians amongst us insist that you need a min of 30 rounds in the data set to get stable ES/SD numbers and with small data sets you are highly liable to see statistical artifacts and not actual ES/SD overall (prob didn't say this right....but best I can do).

Now, I do often run a chrono (I do like the Labradar haha) and have seen this personally as I added more shots to a data set during factory and hand loading shooting.

Just a thought and thanks.

 

[viking78]

Thank you for posting this and I get a kick out of seeing you in short sleeves after watching vids of you and Roni shooting...above the arctic circle! haha ;-)

Just thought....and there have been lots of threads on this with much heated debate....but the statisticians amongst us insist that you need a min of 30 rounds in the data set to get stable ES/SD numbers and with small data sets you are highly liable to see statistical artifacts and not actual ES/SD overall (prob didn't say this right....but best I can do).

Now, I do often run a chrono (I do like the Labradar haha) and have seen this personally as I added more shots to a data set during factory and hand loading shooting.

Just a thought and thanks.

Thank you sir
Well, i had only 10 round a fresh sr Lapua brass, and we had some technical proplems with the chrony.
But when i have shot these lr primer pocket brass, i could do a larger test.
I was wondering, should i shoot the ammo, like 5 sr, and then 5 lr, take a small gap,
do it a again like that.
Or shoot 10 rounds each, make a 5 min pause, shoot the different size primer.
I have only CCI primers at the moment, nothing else available, maybe not even 2023 .
Have you primers in the gun store, like they were few years ago?
When will this shit end.

 

[viking78]

You can’t just tell us? We have to watch a YouTube to pretend we are interested?

I am a dick, a large one

 

[Baron23]

Thank you sir
Well, i had only 10 round a fresh sr Lapua brass, and we had some technical proplems with the chrony.
But when i have shot these lr primer pocket brass, i could do a larger test.
I was wondering, should i shoot the ammo, like 5 sr, and then 5 lr, take a small gap,
do it a again like that.
Or shoot 10 rounds each, make a 5 min pause, shoot the different size primer.
I have only CCI primers at the moment, nothing else available, maybe not even 2023 .
Have you primers in the gun store, like they were few years ago?
When will this shit end.

The shots don't need to be sequential...you can just add data points to the set for LR and SR...just need to keep everything else constant including temperature (thinking of temp of powder on a hot day vs not hot day).

Have you primers in the gun store, like they were few years ago?

Sorry, my friend...but in today's environment, that's funny! haha So, some primers...more than a year ago....but still very, very scarce and I see more SR than LR. Its still pretty awful for powder, primers, etc.

 

[viking78]

THIS WAS WITH THE LARGE PRIMER.

 

[viking78]

WITH THE SMALL PRIMER.

 

[Doom]

Thanks for posting. This is a perfect example of performing a test and comparing the results. There are standard methods for analyzing test data and comparing both means and standard deviations to see if they are statistically significant. For testing two means the test is called Welches T Test which is a variation of Student's T test. For variance/standard deviation its the F test. Using your data here is the result of that analysis:

Mean:
"1. Ho hypothesis
Since p-value < α, H0 is rejected.
The average of Group-1's population is considered to be not equal to the average of Group-2's population.
In other words, the difference between the sample average of Group-1 and Group-2 is big enough to be statistically significant."

Standard Deviation
"1. Ho hypothesis
Since p-value > α, H0 cannot be rejected.
The standard deviation (S) of Group1's population is assumed to be equal to the standard deviation (S) of Group2'spopulation.
In other words, the difference between the sample standard deviation (S) of Group1 and Group2 is not big enough to be statistically significant."

These results were from the following links:

Two-sample t-test calculator (Welch's t-test)

The Welch's t-test calculator provides the p-value, effect size, test power, outliers, distribution chart, and a histogram.

www.statskingdom.com

F test calculator - for the equality of two variances, with solution

The F test calculator provides a p-value with step-by-step calculation, confidence interval, effect size, test power, outliers, distribution chart, and a histogram.

www.statskingdom.com

This doesn't mean that there isn't a difference in Standard Deviation but based on probably and the number of data points we can't rule out the possibility that the results are equal. If we have more data its possible that the results would be different.

 

[918v]

THIS WAS WITH THE LARGE PRIMER.

View attachment 7933262

Can you trust this data? It’s showing 870 “Feet/Sec”. I realize it’s probably a typo but…

 

[Doom]

Good catch but I assume its just an APP error in display. Anyway the comparison is valid for the data.

By the way, in the analysis there are two hypothesis that are assumed.

Ho is that the two values being compared are equal.
H1 is that the two values being compared are unequal.
The test is applied to Ho which if untrue then H1 is true.

 

[viking78]

Can you trust this data? It’s showing 870 “Feet/Sec”. I realize it’s probably a typo but…

I can not get the measure to be m/s on my cellphone, even i do switch it to meter, but the reading is feet, but it its m/s, because i selected it to be so from the chrono.
Software does not support m/s on the driver for that competition electronics, or i am not doing the change right way