.357 Standard vs Mag Primer Test

Hondo 60 · Apr 15, 2017

I did a test yesterday.
Temp 53, Barometric Pressure 30.32

125 gr Hornady XTP
15.8 gr Alliant 2400 (mid range load)
OAL 1.575 - seated at the cannelure

1st batch was with Winchester standard Small Pistol Primers.
1 770
2 864
3 1025
4 799
5 881
6 975
7 866
8 915
9 882
10 816
11 640
12 761
As you can see, velocity was all over the map.
(and I hand charged each case)

With the 2nd batch the only difference was, I used Small Pistol MAGNUM Primers.
"Holy Alter Ego, Batman"!
As you can see, velocity was much higher and more importantly, MUCH more consistent!
(only 11 cuz I had 1 data point that read "Error")
1 1088
2 1066
3 1051
4 1063
5 1064
6 1082
7 1073
8 1046
9 1010
10 1042
11 1018

Many years ago, I asked a regular here about using mag primers.
He said with that small of a charge standard would be ok.
Well I guess my data says only use magnum primers!

dh1633pm · Apr 15, 2017

What brand magnum primer did you use? You results tell a lot.

1KPerDay · Apr 15, 2017

Those results are almost unbelievable!

Haxby · Apr 15, 2017

I've seen similar results with primers in a 38+P load with HS-6.

243winxb · Apr 15, 2017

http://www.shootingtimes.com/ammo/ammunition_st_mamotaip_200909/
Mysteries And Misconceptions Of The All-Important Primer

1KPerDay · Apr 15, 2017

Very interesting article!

Reloadron · Apr 15, 2017

Good read and thanks for sharing that. Looking back to my Speer #12 manual they always call for the magnum primer with 2400 powder, originally Hercules 2400 and now Alliant 2400. The article does mention the use of a magnum primer with spherical or ball type powders. The better results would seem to run with the use of 2400 combined with the magnum primer.

Ron

Hondo 60 · Apr 15, 2017

dh1633pm said:
What brand magnum primer did you use? You results tell a lot.

Both standard & magnum were Winchester primers.
I wanted to use the same brand for better results

Haxby · Apr 15, 2017

Speer #12 manual they always call for the magnum primer with 2400 powder

In Speer #13 they went to standard primers with 2400. Maybe the lighter, lower pressure loads benefit more from the magnum primers.

Hondo 60 · Apr 15, 2017

When I can find some CCI mag, I wanna try it again.
I have CCI standard, but my local store didn't have any CCI MAG.

SASS#23149 · Apr 16, 2017

that is some eye opening results,right there.

Fine Figure of a Man · Apr 16, 2017

It would be interesting to see how small rifle primers perform in 357 mag and or 38 spl.

Reloadron · Apr 16, 2017

Haxby said:
In Speer #13 they went to standard primers with 2400. Maybe the lighter, lower pressure loads benefit more from the magnum primers.

I noticed that and always wondered what drove their logic for doing that. The ball and spherical powders were actually I believe developed during the 1930s but were not really available to the hand loading enthusiast till the early to mid 1950s following WWII. I was always of the thinking that the magnum primers were developed to provide good and complete ignition for the then new harder to ignite powders.

While I have done some experiments using a variety of CCI primers (small rifle) I have not experimented with handgun.

Maybe this summer I will get to it.

Ron

Haxby · Apr 16, 2017

I don't know why Speer changed their primer recommendations for some loads. Speer and Alliant are parts of the same company now, maybe Alliant had data with standard powders and they agreed to go that way. But that wouldn't explain the change with 4227.

Catpop · Apr 16, 2017

Good study!

Milt1 · Apr 16, 2017

Honda, I, like others, appreciate your test! I would like to have seen the results of accuracy as well. It would appear that the 2nd group would have given excellent accuracy but we don't know that? Perhaps in additional test you'll include accuracy as well! Thanks again!

Reefinmike · Apr 16, 2017

All the old timers suggest 2400 because "ya dont need them fancy magnum primers to light it". Thanks for the data! Eye opening!

someguy2800 · Apr 17, 2017

Never shot 2400 but it really gives H110/296 a kick! I tested in 357 herrett, velocity went from 2100 to 2250 when going from a CCI large rifle to large rifle magnum using 296. Extreme spread also came down but pressure was really high. Did the save test with IMR4198 and it made no difference.

PO2Hammer · Apr 17, 2017

Would love to see a test with the CCI 550.

243winxb · Apr 17, 2017

Thank you Hondo 60 for doing the test.

As i posted before. Correct primers for 38 and 357

Reloading data lists these primers to be used with the 357 magnum. CCI 550 Mag., WSPM, FED 200, REM 5 1/2

Reloading data lists these primers to be used with the 38 special and 38special +P. CCI 500,Rem 1 1/2, Fed 100, WSP,

Speer list the CCI 550Mag primer for Alliant 2400. This info is available at all primer manufacture websites.

Ball powder = Magnum primers.

Other threads on the subject.> http://www.thehighroad.org/showthread.php?p=5724195 And more>http://www.thehighroad.org/showthread.php?t=382053

FROGO207 · Apr 17, 2017

Interesting stuff. I have never bothered to crono the 357's that I make. Still the accuracy and felt recoil appeared virtually the same whether I used standard, MAG, or SR primers for equivalent loads so I assumed they were basically the same. :scrutiny:

Now I will have to try some of each of my loads and see if I find a difference as well. I am not sitting at max loads either as I stop going up when I find an accurate load for that particular revolver and they are usually at or just above 3/4 of max load.

Walkalong · Apr 17, 2017

My guess is that the mag primers made a difference because it is such a light load for 2400 and .357 Mag caliber.

I would like to see the test at a higher velocity/pressure level.

Rule3 · Apr 17, 2017

243winxb said:
Thank you Hondo 60 for doing the test.

As i posted before. Correct primers for 38 and 357

Reloading data lists these primers to be used with the 357 magnum. CCI 550 Mag., WSPM, FED 200, REM 5 1/2

Reloading data lists these primers to be used with the 38 special and 38special +P. CCI 500,Rem 1 1/2, Fed 100, WSP,

Speer list the CCI 550Mag primer for Alliant 2400. This info is available at all primer manufacture websites.

Ball powder = Magnum primers.

Other threads on the subject.> http://www.thehighroad.org/showthread.php?p=5724195 And more>http://www.thehighroad.org/showthread.php?t=382053

But Alliant does not list a Mag primer,

Hodgdon lists a Mag primers for anything that says "Mag" even if the powder doen't need one. I asked them about it and it was just for consistency.

For the same weight bullet, Alliant (Gold Dot) the OP charge is a the start load, It is a 2nd to lowest Hornady load and there data is usually pretty conservative,

Most slow (mag) powders seems to do better at the high end,

243winxb · Apr 17, 2017

Walkalong said:
My guess is that the mag primers made a difference because it is such a light load for 2400 and .357 Mag caliber.

I would like to see the test at a higher velocity/pressure level.

Me too.

A 158 gr bullet may make a difference also?

buck460XVR · Apr 18, 2017

Walkalong said:
My guess is that the mag primers made a difference because it is such a light load for 2400 and .357 Mag caliber.

I would like to see the test at a higher velocity/pressure level.

Same here. But still a very interesting and well done test. If I was going to shoot mid-level loads outta my .357s using 2400, I'd definitely try mag primers.

.357 Standard vs Mag Primer Test

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