Monday, May 7, 2012

Follow Up Report on Alliant 300MP

Back in October, I did a post on Alliant's new 300MP powder in a carbine. Those values were for the low end of the recommended load range. Last month I was able to get to a range where I could set up a chronograph so I tested loads at the high end of the range.

  • Gun = Marlin 1894C 18.5" barrel
  • Bullet = Hornady 158 gr XTP/FP
  • Case = Starline 357 magnum
  • Primer = Winchester Small Pistol
  • Powder = Alliant 300 MP
  • Ambient temperature = 88F (prox)
Charge Weight Average Standard Deviation Minimum Maximum Spread
18.0 1,839 4 1,846 1,836 10
18.2 1,853 7 1,844 1,859 15
18.4 1,854 10 1,870 1,841 29

At 18.2 gr -- still 0.4 gr below the maximum recommend charge for 158 gr jacketed bullets -- the XTP slugs were clocking as fast or faster than any commercial ammunition I've tested so far except for the Buffalo Bore 19C. Since Tim Sundles must be in league with the devil I don't really feel too bad about that.

I think I have found my new go to powder for 357 magnum in the 1894C.


  1. I'm glad someone else is looking for a good 158 grain/300-MP load for the 1894! I've only used H-110/W296 a little, but the 300-MP seems to be pretty close in loads and appearance. However, it (apparently) gives a little better velocities. The numbers that I got when I chronoed 16.7-18.6gr 300-MP under a 158gr Hornady JSP are under the 1894 section:

    (Sorted by firearm, bullet weight, powder, and load)

    It looks like mine are pretty consistently 50-100fps slower than yours for a given load, but they're in the same ballpark. My 9/17/2011 tests were at 56º and the 3/17/2012 tests were at 76º. I need to add that field into the table at some point!

    Although components and technique are probably part of it, it seems like the powder is somewhat temperature sensitive. I'm really impressed with your low velocity spreads!

    As far as accuracy goes, I loaded up some 140gr XTP's from 17.5 to 19.5 grains, and they were all in the 3-3.5" group size at 50 yards. Most of that distance was vertical, and I think the glare from brass front sight may have contributed to that. The top of the front sight got Sharpied as soon as I got home. Skinner peep sights rock, by the way, but I'd recommend the blued front sight! I haven't gotten a chance to chrono those yet, but I'll post those numbers on my site when I do.

    Out of curiosity, how much are you crimping your loads? I've read with H-110 you have to crimp the heck out of them, but I hate to do that unless I absolutely have to. I'm crimping these (and pretty much all of my .357's) with a Lee FCD to right where it *just* starts to flatten the case against the bullet, but it's not like the Buffalo Bore lead .38's where it's 1/16" flattened against the bullet above the roll crimp.

    Also, is your 1894 the Microgroove or newer Ballard rifling? Mine's the older Microgroove, but I'm not sure if that would make any difference with jacketed bullets.

    I'll be interested to read about your future results!

    1. On the Hornady XTP, I use a roll crimp into the bullet cannelure. I don't know if it would be considered "light" or "heavy" but it is well short of flattening the case against the bullet. One of the reasons I favor Alliant powders is that they ignite more easily than others (mostly Hogdon) I've tried. Consequently I adjust my crimp based on bullet jump in the revolvers or setback in the levergun. I've never had any of the Alliant powders I use (Bullseye, Power Pistol, Unique, 2400 and 300-MP) leave behind a lot of unburned grains or pepper people to the side with "sand".

      The rifle I shot for the above results from has Ballard rifling. I recently acquired an 1894C with the micro-groove rifling that I intend to test next time out. I only have an opportunity to set up the chronograph two or three times a year so it may be a while.


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