Let's talk about Power Pro 300-MP

[Nick_C_S]

For magnum revolver rounds, I've been loading with W296 (currently have H-110) since 1985 and it is without a doubt a stellar propellant for the application. But as most know, it doesn't download well. So I have also been de-tuning a bit for my revolvers, using 2400, in these later years of mine (recoil isn't as exciting as it used to be).

I have 357 Magnum revolvers in 3", 4", 6", & 8-3/8" bbls. I also have a Henry rifle, 16" bbl.

I have 44 Magnum revolvers in 5", & 8-3/8". I also have a Marlin rifle, 20" bbl.

So as you can see, I have a lot of barrel lengths for which to load ammo.

As already mentioned, I have been using 2400 quite a bit these days, reserving the W296 almost entirely for the rifles.

For this thread, we really only need to talk about 158gn jacketed bullets. I've seen 300-MP around for years and just kind of figured it's more or less 2400 on steroids. Just my guess. But for about a year now, I told myself if I ever cross paths with 300-MP, I'll grab myself a # of it just to try out. During this latest shortage, as powders have been coming back on the shelves, I couldn't help but notice that Alliant products have been conspicuously missing - until yesterday. Yesterday, I poked my head into the Sportsmen's here in Twin Falls and they had a few Alliant products. There was Power Pistol, Unique, an 8# container of Bullseye (would have grabbed if I wasn't sitting on 10#'s of W231), and a couple others that I now fail to remember (I think AR Comp and Herco??). Anyway, there was also (2)#'s of 300-MP, so I grabbed a #.

My thought is for use in the rifles; save for a few rounds through the revolvers for the novelty of it. But definitely the loads will be tailored for the lever-actions. (Side note: If I crossed paths with Hornady's 180 XTP's, I definitely snag a box or 4.)

My Henry has a diet of only Everglades's 158 JSP's, with an amount of W296 that I believe slightly exceeds current published data, so I side-step the charge weight. It chronos at 1799 through the Henry, and 1270 through my 4" 686. At any rate, that is the only load I feed my Henry.

But now that I have 300-MP, I'm going to give 'er a try. And the Marlin 44 Mag too. I'm in no hurry as I, A): have lots of other load testing irons in the fire - if it ever gets warm enough to get to the range. And B): I have lots of ammo already loaded for my rifles, especially the Henry. (Off topic, but that Henry is sure fun to shoot - I just love it.)

So I am curious what other folks have experienced with 300-MP. I couldn't help but notice that there isn't much load data for it, but that doesn't really concern me much. Hornady has data; as well as Alliant's site. It's not a lot, but it's enough to get a work up started. I mostly just want to know what other people's experience with is has been.

Thanks in advance. - Nick.

[ligonierbill]

First, I am shooting a 4" GP-100. The short story is that 300-MP is the only powder I tried that would match Hornady's 125 commercial defense loads. They went 1,430 out of mine, and I recorded 1,463/14 Std with Sierra 125 JHC. Mostly, I shoot 158s, and I got pretty high Std with 300-MP compared to H110 and AA#9 (my current choice). Alliant tech support told me to ensure I had a good crimp, which I thought I did. In any case, with that one exception, I quit running 300-MP.

[tlm225]

I went with 300MP for my Marlin 1894 in .357 (18 1/2" barrel). Using a Remington 158 JSP I worked up to a load 3/10 of a grain under Alliant's max which yielded 1890 FPS. That added 200 FPS over what I obtained with a book maximum charge of 2400.

[Unclenick]

Good powder, but, if anything, even harder to light consistently than H110/296. I recommend not only a magnum primer but a really firm crimp. The Redding Profile Crimp Die would be a worthy investment for loading that powder. A conventional crimp die plus the Lee Collet Style Factory Crimp Die for 357 is something else I would expect to see do the job, too, but I can't claim to have tried it with 300-MP, as I ran out before getting the Lee die.

[Nick_C_S]

The Redding Profile Crimp Die would be a worthy investment

I have one. Haven't really tinkered with it much though. This may be the right time.

Thanks Unclenick.

[Nick_C_S]

I recommend not only a magnum primer but a really firm crimp.

I went with 300MP for my Marlin 1894

tlm225: What primer are you using?

Hornady uses a WSPM for their data. In fact, they use a magnum primer for all their 357 Magnum data. It was just today that I realized that .

Fortunately for me, I have a lot of CCI 550's.

[Sevens]

I have been using gobs of this powder in .357 Magnum but I've only used it for 158 grain jacketed bullets thus far.

I can report that velocity returns were nearly exactly the same whether I was loading 18.0 grains or 18.5 grains under the Zero 158gr JSP and because of this, I've simply settled on the 18.0 grain charge weight. All my full-boat .357 Magnum loads are run with small rifle primers, varying from CCI to Winchester to S&B before I ran out of those.

Average velocity I've seen was 1,320fps from a 6-inch S&W Model 28-2 on your basic 72-degree sunny day.

I've only dabbled with this powder in other places. Disappointing velocity returns in .327 Federal.

Like all Alliant powders, I find the supplier's load data to be lacking.

[tlm225]

Originally Posted by Nick_C_S

tlm225: What primer are you using?

Hornady uses a WSPM for their data. In fact, they use a magnum primer for all their 357 Magnum data. It was just today that I realized that .

Fortunately for me, I have a lot of CCI 550's.

Sorry for the delayed response, had to dig out my notes.

I used CCI 500's, standard small pistol. 20 FPS spead (1881-1901 FPS). I did use a good firm roll crimp in the cannelure. No signs of excess pressure on the primers and easy extraction.

[Nick_C_S]

tlm225: Thanks for the info. No worries on the delay; I've been busy too.

I have been using gobs of this powder in .357 Magnum but I've only used it for 158 grain jacketed bullets thus far.

Well 158 jacketed is pretty much all I will be using it for, so that's all good. Maybe 180 XTP's if I ever run across any.

S&W Model 28-2

Nice gun. I saw one in very good condition (4"bbl, if memory serves) at my LGS about 10 years back and passed on it. Yeah, that was a mistake. I still think about that one that got away every now and then.