357 Magnum Is A Beast: Is It The Best All Purpose Caliber?

| November 27, 2022 | 5 Comments

357 Magnum has a long history and is still going strong today. This caliber really comes alive in the hands of a reloader when used in a longer barrel carbine. Though I am very found of 357 Magnum it is third on my list of favorites behind 44 Magnum and 10MM. The question is have I given 357 magnum a fair shot at reigning supreme?



“The” Test

Well there is only one way to find out if I have been fair or not and that was to develop a test. The test would consist of firing rounds across the chronograph and into some ballistics gel. Now I personally believe 160gr-170gr freedom pills are the optimal weight for this caliber and  capable of meeting all demands. 158gr Hornady XTP’s are proven to get the job done but within a specific window. To low of a velocity out of a short barrel and no expansion, push them to hard and they expand to quickly with not enough penetration. The 180gr XTP’s take up a lot of case volume due to their length. This can limit the speed creating less expansion but great for hunting with needs for deep penetration. This is where I turn to my friend Big E to cast me some 170gr freedom pills. The thought process is with the right magnum velocity this bullet would not over penetrate out of the 2in Ruger Security Six, be optimal at hallway distance out of a 4inch S&W 686Plus and a deep penetrator for hunting purpose out of a 6.5in Taurus Tracker or 16in Marlin 1894.


What Is The Right Hand Load

Now that I have the Big E bullets in house it is time to work up the right load. Most everyone in the reloading community turns to H110 for magnum load responsibilities, its understandable it is a proven performer. We also accept some of it’s warts that come along with it, extreme flash, narrow load window and high pressure. Lately there has been a lot of internet conversations taking place about Alliant 300-MP.  300-MP caught my eye because it fills the case a bit more, some would say that makes it less efficient. Needing more powder to generate the same speeds. I consider it a safety mechanism against a double charge. This powder also generates less pressure at the same velocities as H110 according to the perspective reloading manuals. Most of all 300-MP has a flash suppressant added minimizing that dreaded muzzle blast. For this reason alone I truly wanted to try some and wouldn’t you know it a trip to the local reloading watering hole exposed ALOT of 300-MP on the shelf. Because of the flash/muzzle blast and percussion I have never considered 357 Magnum suitable for home defense firing in close quarters. Can 300-MP potentially help with that also?

I decided why not test both?


Load Used

This data is not intended to replace the appropriate reloading manuals data and should not be used without verifying and double checking the loads between two different official published reference points — IE reloading manuals. If you elect to utilize any of this data it is at your own risk, you take full ownership and responsibility for your ammunition.

H110 15grains of Powder, 170grain Hardcast SWC – C.O.A.L 1.635 Federal Small Pistol Magnum Primer – Hodgdon Book Recipe 14grains – 15.5grains COAL 1.580

Alliant 300-MP 16grains of Powder, 170grain Hardcast SWC -C.O.A.L 1.635 Federal Small Pistol Magnum Primer – Alliant Book Shows a max load of 17.5grains COAL 1.590

Another general warning I decided to crimp these specific 170gr cast bullets at the crimp groove which made them longer than they should have been. There are a couple of issues here. First without a tight enough crimp you risk crimp jump and locking up your revolver. Secondly these rounds got jammed up really bad in the Marlin 1894. The ideal length for these rounds would have been 1.600 to have fed properly in the Marlin.

Testing/Velocity Results

The velocity was taken with a Competition Electronics Pro Chrono DLX 6 Yards back from the chronograph. The manual actually states 3 yards is best but I have seen after years of testing that unburned powder in some loads can fly across the chronograph and produce inaccurate readings.



Gel Test Results

357 Magnum proved to have more punch than I thought. Also if you are paying attention to the load data you will see that H110 is .5grains below the max recommended load. 300-MP is a full 1.5grains below its advertised recommended max load. This fact and examining the velocity it seems Alliant 300-MP lives up to at least one of it’s claims in producing greater velocity with less pressure. Though neither of these loads show pressure signs I never go beyond what’s recommended for safety reasons and for the fun of it. The fun of it means if I need to go beyond recommended loads, means bumping up and going to a larger more capable caliber for the intended task, which is always fun in my view. This all will lead to another test after Big E cast some of our own freedom pills. But before I spoil it for you just watch the video. 

Article Update As Of 12/4/2022

After cleaning the revolvers I have noticed something I have never seen before. I did notice this same brown looking unburnt powder on my chronograph down range also. This is the very reason I stand at minimal 7 yards down range from the chronograph, to keep unburnt powder granules from causing false readings. This same brown looking material which I believe to be unburnt 300-MP powder was in the barrels of each revolver. It wasn’t bad but perplexing. As this material looked a little like crushed walnut though on a much smaller scale. If I were not in the practice of wet tumbling my brass now I may have mistaken it for my dry tumbling media. So for awareness it does seem that 300-MP is dirtier than H110 but not enough to cause an issue or to make me stop using it.  😁

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5 Comments on "357 Magnum Is A Beast: Is It The Best All Purpose Caliber?"

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  1. Franklin says:

    OK, the 357 Magnum is a great cartridge. Given.

    So, where’s the rimless version designed for semi-autos? (This assumes semi-autos in plentiful quantities would exist for a cartridge with the OAL of 357 Magnum Rimless).

  2. Lenny says:

    Really enjoyed this video! I am new to reloading and found it informative. Ironically I loaded some 38spec and 357 mag the same day before I watched your video. Thanks again for the work!

  3. Glad the content was useful to someone that is awesome. Lenny if there is something I can help with as you make this reloading journey let me know.

  4. Chet says:

    Great video. .357 mag is my favorite cartridge. I enjoyed that you covered the spectrum on barrel lengths. I think the 170 is heavy for self defense. I prefer 125 grain for that. As far as 170, at 1700 fps for whitetail deer goes, it would absolutely be a deer killer inside of 150 yards.

  5. wardrive says:

    Is that the 6.5 inch Tracker 627?

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