9mm and 300 Black

Looking for some outside information on this topic. I jumped on the 300 about a year ago due to the ease of having one. I’m one of those guys that “needs” to have a truck load of magazines for everything that I own so the 300 made sense there. I also “need” to have a truck load of ammo for everything that I own, and this is where the 300 is failing me. Currently I have “enough” 223 and 9mm due to a Dillion 650. This has had me looking at the 9mm subguns, mainly the scorpion.

With all of that said, my question is, from a purely defense/fighting stand point is the 300 any better than the 9mm? You can have both is super and sub sonic, does that even matter?


I’m not super smart on things but I’d guess the 300 black has a bigger pill and more powder


300 blackout has ballistics closer to a 7.62x39mm in some cases, its a fat slow rifle round. The 9mm is a handgun round, cant give you specific numbers but I would prefer the 300 for shooting anything fleshy.


Not really, both are deadly

9mm will be far easier to wield in close quarters, quicker target acquisition

but 300 will be heavier hitting

I like both


Edit: In looking at other responses maybe I misunderstood. :smiley:

I don’t have my .300BLK yet, but I’m about to give you my vast amount of knowledge re: it. Actually, while I jest about my lack of experience with the cartridge I have studied it quite a bit. I’ve had plenty of time to do so while I wait for mine.

There are 2 schools of thought when it comes to hunting and dispatching animals, no matter the circumstance of their demise or the number of feet. One school says fast and light bullets and the other says slow, big, and heavy. To confuse the issue for .300BLK there is a 3rd school that uses slow heavy bullets that expand.

All 3 work, just differently. It’s been my experience that light and fast bullets work faster if the bullet is designed properly to expand for the velocity it’s being loaded for. With .300BLK they can easily reach 2k fps and that’s enough for actual stopping power. No handgun cartridges that most folks would consider for SD can be said to have actual stopping power. It’s extremely efficient to raise the velocity of the bullet to give it more energy, and more energy is a really good thing. Indoors a silenced round is good IMO. Yes, these can have the blast suppressed and the blast experienced indoors will destroy ears extremely fast. But the supersonic crack will still exist. But it’s much more ear friendly than without a can. I suppress my supersonic HD rifle to make it usable indoors.

In the slow, heavy category, they work, just slower since there is no temporary wound cavity to speak of and no stopping power as with the fast, light school. Too, penetration is sort of phenomenal since many, but not all, bullets used here won’t expand, they just zip right through. This would NOT be my first choice for home defense due to collateral damage. Remodeling rooms can get expensive and what isn’t lost to burglary will be spent on remodeling. Is a .30 cal effective in this subsonic category? I think I would want a bigger caliber, but that’s me. If I’m going to throw a rock I want it to be a big one to get the point across as fast as possible. Too, the only way to get more energy on target since this is subsonic limited is to make the projectile heavier. That gives even more penetration and I already discussed that potential problem. It’ll work though. Oh, and it can be nicely silenced making it nice on the ears.

In the 3rd category are heavy expanders. Much the same as above, except expansion cuts down on penetration. I haven’t tested these, as I already explained, but I like the idea. With a can on the gun they can be friendly to ears, reduce the remodeling greatly and should rearrange the innards of the target quite nicely. These bullets alone (for reloading) are quite expensive but available. Just do a 'net search and you’ll turn them up. I’m terrible at remembering names but is Lehigh one brand?

Too, and you didn’t ask this, there is a manufacturer making bullets specifically for .300BLK that are relatively inexpensive for practice and what not. What good is a cartridge that’s too expensive to shoot? Most heavy bullets for it are designed for much more critical roles and are priced that way. Using (and paying for) the same jacket required for a “reach out and touch” cartridge is huge overkill for .300BLK. Copper plated bullets are just the ticket though. Again, names and I don’t mix at all well… Let me see if I can find it. (Footsteps retreat, then come back minutes later.) Berries.


There are at least 2 retailers that carry them as of a year ago and probably more today.

Please let us know how you make out.

Edit: FWIW, I wouldn’t want to be hit with either a .300BLK or 9mm. I use that as the yardstick to judge effectiveness.


I’ve shot a lot of this stuff without a hitch. some don’t like others reloads, but…


Geez another long post.

If you want a sub gun, get a 300 blackout barrel, if you want a super sonic go with 300 HAMR.

The case for the HAMR is one millimeter longer than the x39. It equates to a semi auto 30-30.
It will stomp a x39 ballistics.

This is about the 300 blackout. Subsonic the 230gr cast boolit is like a 45 ACP out to 100 yards!
I make those for the Mrs 300, The daughter uses 110 and 125gr varmint grenades super sonic.
So they use both schools.

The 300 BO was designed to replace the MP5 9mm sub. It works so well at that some of the Euros have now converted.
Bullet over 135 grains will not expand. Even the Amax dont open up. We tried. We use 150s for practice because I have 10,000 of them. For combat use, the Lee 230 Blackout boolit mold.
You are using a 35mm case, not a lot of room for powder.

The 230 gr lead boolit along with bleep amount of Lil Gun powder out of a 10.5 barrel goes a tad under 1000fps. No crack, and with a can as quiet as a 22 rimfire thru a pillow.

The cases are cut down 5.56 cases. there are a lot of videos showing you how to make them.
We made 5000 in a day. (went thru a metric bleep ton of cutting discs)

It does not matter who’s 230-250gr pill you use. They will thump a target like a 45ACp out to distance. I can do the 200 yard gong with the Mrs, she can not.

Psst gang, a lead boolit leaves no rifling marks, they splat on contact. But then neither do paper patch boolits. (different thread)

The old 9mm VS 45ACP. The 45 wins hands down in this case. NO 9mm has the energy of a 300BO.