First .300 Blackout Handloads with M80 Pulls and Alliant 300-MP

| April 2, 2014 | 4 Comments

We plan on shooting between 4000 and 5000 rifle rounds this year during training. Ideally we’ll use our .300 Blackout rifles, and that means either a ton of money for loaded ammunition (about $0.40/rnd when you can find it) or a ton of time hand loading.

We chose to hand load because I don’t like being dependent on retail conditions for ammunition. I also like the idea of saving even more money on loading our own self defense ammunition instead of paying $1.20+ per round for equivalent retail ammunition.

I’ve covered what you need to do to convert 5.56 blanks to .300 Blackout brass, and the M80 .308 caliber military surplus pulls I purchased.

I’m using Alliant’s 300-MP for my powder. I took some established loads from other shooters on that used 300-MP with their own M80s.

I made a “ladder” of .300 Blackout handloads.  A “ladder” is at least three powder ranges, ranging from the safest, to a little more powder / faster load, and then an even more powerful load. In my case, I did 17.0, 17.2 and 17.5 grains of 300-MP

Unfortunately there aren’t many indoor ranges within an easy drive that allow for rifles. Worse yet, the range is shared with pistols, and only goes back about 15 yards. I was only able to function test my hand loads, and do not have any chronograph data or even really any accuracy data aside from basic grouping.

All rounds were fired standing and unsupported via my 6.5″ barreled .300 Blackout AR pistol.

Firing impressions

I’ve reloaded a ton of .40 S&W and .45 ACP in my days, but this is my first experience hand loading rifle rounds. I was amazed at how much difference half a grain of gunpowder made in my ladder.

The 17.0gr load was pleasant, despite not having a stock on my AR pistol. I felt like the 17.2gr load had more oomph to it, and perceived recoil was worse. I did not notice an appreciable increase in accuracy at the short distance I was shooting at.

17.5 grains? That felt like a whole different caliber, like going from 5.56 to 7.62×39.

None of the 17 grain loads showed any sign of case deformation, ejector swipes or primer damage. One of my 20 17.2 grain loads showed a weird pattern on the headstamp. I’m not sure if that’s due to pressure or just an oddity.

Four of my 17.5 grain loads showed ejector swipes, and two of those had cracked rims.

All loads fed fine through my MagPul Gen 2 and Gen 3 PMAGs. All locked the bolt back on the final shot. PMAGs have a reputation in the .300 world for not feeding as well as other mags, so I figured if this load worked with them they’d work with my Troy and USGI mags.



I was sighting in my Primary Arms red dot sight at the time, so please pay more attention to the groups than my point of aim. My best group with recipe #1 was near the 8 (one’s in the black). The best group for recipe #2 is near the black ring.



The groups in Recipe #3 are a little more open, but all of the groupings are probably due to operator error.

The purpose of this visit was to check function of my M80 pulls and the Ice Arms barrel, it will be interesting to see how things go once we can start training outside again.


  • Powder: Alliant 300-MP, 17.0 grains
  • Bullet: .308 M80 military surplus, FMJ
  • Primer: CCI #400 small rifle primer
  • Brass: once fired Lake City 5.56 blank brass converted to .300 Blackout via a Lee full length resizing die
  • Brass length: 1.360″
  • Cartridge overall length: 2.015″

NOTE: this works in my AR with my setup and may not work for your AR. Use this information at your own risk, and do your own ladders.


Despite the irregularity of the M80 bullets and the reduced accuracy compared to other projectiles, the loaded cost of these rounds is very attractive.

Not including starting equipment or my time, the loaded cost per round is $0.235 each. Brass and projectiles are the most expensive part of .300 Blackout hand loading, and by using reformed blank brass and milsurp projectiles I was able to keep my costs down.

My loaded cost was less than the average cost of reformed 5.56 brass alone. There are several members offering reformed, polished cases for about $0.25 delivered, and it pleased me to put my whole cartridge together for less than that.

Handloaders like to say that “rolling your own” isn’t cheaper in the long run, you just wind up shooting more for the same cost. I think that’s definitely true, and I look forward to training with our .300 Blackout hand loads this spring and summer.

About the Author:

Short Barrel Shepherd Short Barrel Shepherd is a regular guy and works to make Web sites and mobile apps easier for people to use. He spends his free time attending fight-focused firearm, knife, and combatives training, motorcycling, writing, and playing games. His daily carry is a Glock 19 pistol and an AR15 .300 Blackout pistol in a backpack.

4 Comments on "First .300 Blackout Handloads with M80 Pulls and Alliant 300-MP"

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  1. bond says:

    What’s interesting about 300BLK right now is that you can make quality ammo for a little less than factory; however, you can’t buy factory ammo at all, high or low quality. The reason I started reloading was so I could “have” some 300 BLK, it’s just too hard to find for sale. The price of the reloads isn’t as important as the simple matter of having ammo to shoot. I’d like to get some cheaper loads going like your post above, but I’m super happy with Varmageddon 110gr for around .62 per round. These easily cost over a dollar or more to buy; again try to find them for sale!

    My point is that super high quality rounds can be hand-loaded for a decent cost, but there aren’t tons of cheap reload options for 300 BLK as there are for other calibers. I’m OK with this in the short run.

  2. Pierow says:

    In the summary you said that your brass length is 1.60″. Shouldn’t that be more like 1.360”?

    • Short Barrel Shepherd Short Barrel Shepherd says:

      Yes, definitely. I left out the “3.” Thanks for pointing it out, I fixed it!

      • Pierow says:

        Glad to help. I really love your site by the way. Thanks to you I’ve spent the weekend wet tumbling, cutting and resizing 5.56 brass into 300BLK.

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