.357 Magnum 125-gr CPHP Chrony data

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.357 Magnum 125-gr CPHP Chrony data

Postby Morne » Sun Jan 15, 2017 4:59 pm

Meteorological Data: 33 F, 59% RH, 30.39" Hg

***CHRONY DATA***

.357 Magnum 125-gr CPHP, WSP(m), Accurate #5 Powder, 1.562-1.582" COAL
Taurus 66 with 6" barrel five (5) shot strings each
8.8-gr powder - AVERAGE = 995 fps - ES = 61.2
9.1-gr powder - AVERAGE = 984 fps - ES = 63.9
9.4-gr powder - AVERAGE = 1061 fps - ES = 93.0
9.7-gr powder - AVERAGE = 1080 fps - ES = 172.4
10.2-gr powder - AVERAGE = 1085 fps - ES = 104.0

.357 Magnum 125-gr CPHP, CCI-500 SPP, W-231 Powder, 1.575-1.582" COAL
Taurus 66 with 6" barrel five (5) shot strings each
7.6-gr powder - AVERAGE = 1116 fps - ES = 149.0
7.9-gr powder - AVERAGE = 1158 fps - ES = 109.0
8.2-gr powder - AVERAGE = 1209 fps - ES = 43.0
8.5-gr powder - AVERAGE = 1261 fps - ES = 58.0

The above is already better than the awful data I got before with IMR PB and HS-6. Here's the problem, though - I'm not happy with this velocity. I'm looking for something that'll do close to 1500 FPS.

Am I using the wrong powder? Should I try upping the load on that W-231 recipe? It is currently at the maximum that Hodgdon recommends in their data center but here's a picture of the primers from that 8.5-gr load:
Image
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Re: .357 Magnum 125-gr CPHP Chrony data

Postby Sevens » Mon Jan 16, 2017 8:57 pm

1,500 fps even from a 125gr in .357 Mag is hardcore territory. A copper plated slug (is it Ranier?) is not at all a good slug for this job, and you need a slow burning magnum powder.

2400, AA#9, H100/W296... even that Lil'Gun that I would never use in a revolver haha, any of those powders give you not only a much better chance to get near 1,500... any/every single one of them is FAR more safe for even attempting.

If you could plot the pressure curves on a line graph, the line would look like a pro-class craggy cliff such as Everest. The fast burning powders rise in peak pressure sharply, early, and with no warning. Attempting max velocity in large cases with fast burning powders is the finest route to destruction.

Try 2400 and you'll not only go faster... you will be much safer. And the line graph would look like a proper hill that rises in elevation and comes to a predictable and safe peak without a ridiculous spike going directly upward.

And get some proper jacketed bullets. If money is no object, Hornady XTP or Sierra or Nosler. If money is the main issue... Montana Gold or Zero/Roze or bulk pulldown. Even Xtreme makes a thicker layer of plating than Ranier.
I like to swap brass... and I'm looking for .32 H&R Mag, .327 Fed Mag, .380 Auto and 10mm. If you have some and would like to swap for something else, send me a note!
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Re: .357 Magnum 125-gr CPHP Chrony data

Postby Morne » Tue Jan 17, 2017 12:07 am

These are X-Treme plated.

I have some accurate #7 I can try. Thoughts on that powder? Does it call for magnum primers?

Won't use Lil' Gun with the lightweight bullets. That is where things get bad with that powder. I save the Lil' Gun for moderate to heavy bullets only. That means for .357 I use it for 158-gr slugs. For .44 I use it for 240-gr slugs. In my .357 125-gr or my .44 200-gr I use something else...anything else... :idea:
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Re: .357 Magnum 125-gr CPHP Chrony data

Postby Sevens » Tue Jan 17, 2017 1:07 am

I definitely think AA#7 is more appropriate, maybe Power Pistol if you have that (which I think runs in similar circles to AA#7). I still like AA#9 and 2400 better, especially if you go to heavier slugs.

The Lil'Gun is a slow burner... I do NOT like the throat erosion you will get, but it is more appropriate than AA#5 or W231 for trying to get to 1,500 with a 125.
I like to swap brass... and I'm looking for .32 H&R Mag, .327 Fed Mag, .380 Auto and 10mm. If you have some and would like to swap for something else, send me a note!
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Re: .357 Magnum 125-gr CPHP Chrony data

Postby Sevens » Tue Jan 17, 2017 1:15 am

Forgot primers...
Been my experience with AA#9 that it doesn't "require" magnum primers or run erratically without them... but you can sometimes pick up some velocity with them. I have never used them with AA#7... but simply for the ease, I just use small rifle primers in -ALL- my .357 Magnum handloads.

With one caveat, haha... 2400 has always performed better with non-magnum pistol primers. I've heard reasonable theories on why this may be but I don't recall absolute specifics. Something about the possibility that the magnum primer itself has a tendency to maybe begin movement of the bullet and 2400 simply doesn't benefit from a hotter primer...?

Interior ballistics is a morass of black magic that is far beyond anything my pea brain can sort out. :P
I like to swap brass... and I'm looking for .32 H&R Mag, .327 Fed Mag, .380 Auto and 10mm. If you have some and would like to swap for something else, send me a note!
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