Unique. What to expect

Nick that us absolutely fascinating! Really, thanks for putting the effort into this and posting those results. I learned more from that single post than almost anything else I've read. The results go against all logic, to me anyway.

By impending pressure spike do you mean that, maybe even at 9.7 grains, a pressure spike is imminent? If 9.7 fell within the allowable range. I don't mean to suggest going over published data.

The results you posted are not at all what I expected.
 
maybe even at 9.7 grains, a pressure spike is imminent?
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Just to be clear: I don't know a pressure spike was imminent. I'm just saying that the data has that appearance. (And further, not all pressure spikes "pre-warn.")

If - if - that's what was happening, the rapid upward surge in pressure was probably several 1/10ths down the road; 3, maybe 4 - not likely to be at 9.7gn.

We're never going to know ;)
 
Ha! Yeah no, I definitely don't want to find out where that point is.

But, generally speaking, if I'm working within the allowable range and I begin seeing these symptoms it's time to stop.
 
I'm working within the allowable range and I begin seeing these symptoms it's time to stop.
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If you're up in the high end neighborhood of reliable published data - and assuming your charge weights are accurate - then yes, it's time to stop. Variables abound and so it's hard to just put a hard and definite stamp on how to respond to any given situation. I've done workups for some time and I've seen lots of weird things that defy logic. Keep in mind, when you're working up .1gn at a time (which is not always necessary, btw), don't expect every step up to have a higher velocity than the one before. Sometimes there will be a dip, but the overall trend line should be upward. In my Unique example above, the trend line was flat, then downward at the top end - very concerning.

Pressure spiking aside, Standard Deviation is an excellent indicator of a load recipe running well. When you're seeing consistent results - shot after shot - that is probably a keeper recipe. Even if it is not the velocity champ (and it rarely is). Using my Unique workup above, even if the velocities had a steady upward trend line, I probably would have still settled on the 9.2gn, due to its excellent SD.
 
Well now I'm wondering what causes low and high SD's in loads. What I mean is, I wonder why 9.2 had such a low SD and the other charge weights had higher. I'm guessing it has to do with the pressure curve being inconsistent at that charge weight. This is all very fascinating to me and yet utterly confusing at the same time. I'm enjoying the ride though and look forward to putting some of this new knowledge to use.
 
I wonder why 9.2 had such a low SD and the other charge weights had higher.
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I don't know. But what I do know is that some charge weights work better than others. And it could be gun specific. Just one more reason to load your own and test the results with a chronograph.

I'm guessing it has to do with the pressure curve being inconsistent at that charge weight.
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I don't profess to know all the dynamics that transpire when firing pin meets primer. I do know that a whole bunch of stuff happens in a very short time. And it's safe to say that the "stuff" doesn't always unfold exactly as designed.

Some things I just accept. As a small scale handloader, I use the data I have to build the ammo that works for me; and it seems to work.
 
By glance (I did not take the time to run a rigorous statistical test), it looks like the is no statistically significant difference in your chronograph values in the x-value range 9.2 - 9.5. Given this plus the small 0.1 grain step, and I'd be hesitant to draw any conclusion from this data.
 
I have concluded that 9.2gn of Unique is where I'm most comfortable loading a 125gn JHP in 357 Magnum.
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You've tested it, it works in your gun, you're good to go.

Now, here's some figures from the past to boggle your mind (and compare with the Speer#14 max of 9.6gr

125gr .357 Mag, Unique max listed:
Speer #8 10.5gr test gun S&W M27
Speer #9 9.0gr test gun Ruger Security Six
Speer #10 9.1gr test gun Ruger Security Six
Speer #11 9.1gr test gun Ruger Security Six

Hornady 2nd edition 9.4gr test gun S&W M27
Hornady 3rd edition, Unique not listed with 125gr .357
Hornady 7th edition, Unique not listed with 125gr .357

interesting, isn't it?
:D
 
I got to using Unique again after I ran out of W231 not bad at all . I also use a RCBS Un-Flo and can not find my small barrel . I have been using the large barrel and hope it does better when if do find the small barrel .
 
I don't care if it's dirty because of the RESULTS

I use 8-9 grains in 41, 44Spl, 44mag, and 45Colt with the appropriate hard cast bullet. As stated above, the higher pressure loads are pretty clean. A 10gr load under the 275 in the Colt leaves little residue. I've never had a problem metering it in my old RCBS Uniflow and my current Lyman 1200 DPS3.
 
@Nick_C_S just wanted to pass along I just loaded and fired 12 rounds with a charge of 8.7 grains (Sierra book lists 9.2 as max) and a 125 grain Sierra jhp. Now, I don't yet have a chronograph but that load shoots really well. Impact is basically point of aim and they're coming out the bbl with some authority, but very manageable to shoot. Not dirty at all. No signs of pressure. I'm going to order a chrony this week and I definitely think this load has some potential.
 
Yes MightyMO1911, Unique under a 125 JHP in 357 Mag is right in its wheelhouse.

Coming out with some authority is right. Yes, you can squeeze more velocity out of other powders, but 1300-ish fps (with just a 3" bbl) is plenty of poop for SD, yet still manageable.

I like the combination.
 
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