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10/20/2014 7:40:15 PM EDT
Some threads a short while back about primers got me thinking about how much difference is there between primers, so a friend and I put together a little test.














We assembled six different groups of ten .40 S&W cartridges.  We eliminated as many variables as we could.  We used the same case, bullet, powder, OAL, and test pistol, but used six different primers.  One of the primers we used was Winchester Small Rifle primers, as I saw questions about this in another thread.  The load is a mild load I use for plinking.




















Here's the results:















Load:





180 gn SNS Powder Coated FP; 3.6 gn Red Dot; Federal Case; OAL 1.125"





























































































































































































































Primer Avg. Vel. Std. Dev.
Winchester Small Pistol (WSP) 795.7 fps 18.7
CCI 500 Small Pistol 809.8 fps 12.3
CCI 550 Small Pistil Magnum 814.2 fps 15.9
Winchester Small Rifle (WSR) 816.4 fps 11.0
Tula KVB9 825.7 fps 6.3*
Winchester Small Magnum Pistol (WSMP) 859.9 fps 18.1









* Only 6 out of 10 shots registered on chronograph







Not sure I can draw any major conclusions.  


It doesn't change my opinions on re-working up load data if I switch primers.  


There is an 8% velocity difference between the slowest and the fastest.


I wouldn't hesitate to use WSR primers for WSP primers in a pinch.  The test pistol had no difficulty with them.







Anyway, FWIW.

 
 
 
 
 
 
10/20/2014 8:12:27 PM EDT
[#1]
Do you happen to have your raw data (shot for shot)? I could run a quick single-factor ANOVA for you.
10/20/2014 8:13:39 PM EDT
[#2]
Cool, thanks for the info. Looks like the WSMP gave a pretty good bump in speed.
10/20/2014 9:02:41 PM EDT
[#3]

Quote History
Quoted:


Do you happen to have your raw data (shot for shot)? I could run a quick single-factor ANOVA for you.
View Quote
Sadly, I didn't think to save the raw data, just the high, low, avg and sd.

 



Thanks for the offer, though.
10/20/2014 9:13:43 PM EDT
[#4]
Very cool test!

I've heard there's very little to no difference between WSP and WSR.
10/20/2014 9:27:56 PM EDT
[#5]
Quote History
Quoted:
Very cool test!

I've heard there's very little to no difference between WSP and WSR.
View Quote


I would say that his data clearly shows that.

A 20FPS is damn near = to zero when it comes to reloaded mixed brass rounds.
10/20/2014 10:52:58 PM EDT
[#6]
If you try this with rifle loads- you'll see more of a difference- atleast in my experience.

Also maybe 50 of each would really show any differences with a larger number of rounds.

10/20/2014 11:35:47 PM EDT
[#7]
RC rifle showed around a 50 fps difference
10/21/2014 12:14:22 PM EDT
[#8]

Quote History
Quoted:


Very cool test!



I've heard there's very little to no difference between WSP and WSR.
View Quote


Some years ago I talked to CCI's tech support and asked what differences there were between their SPM and SR primers.  After reviewing the spec sheets, they confirmed that the two primers shared the same design, cup thickness, overall dimensions, primer media, and primer amount.  In short, they had identical specs.



 
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