Are there any good comparisons/tests out there between the two?

It seems everyone concentrates on the subsonic loads.

I’d like to see some comparisons done between the two with regards to POA/POI.

I’m not sure what you mean. Are you asking what the difference in bullet drop between the two is?

If so, let’s call it roughly a foot at 100 yards. Obviously the exact loads and rifle will cause it to vary, but that is close enough for general purposes.

quote:

Originally posted by esdunbar:
I’m not sure what you mean. Are you asking what the difference in bullet drop between the two is?

If so, let’s call it roughly a foot at 100 yards. Obviously the exact loads and rifle will cause it to vary, but that is close enough for general purposes.

That’s some of it.
I was wondering if anyone had actually applied both versions in the real world.
I realize different loads are gonna act different....I probably don’t want to try 300 yard shots with a sub sonic load, nor complain about a supersonic load not being “Hollywood quiet”.

It just seems to me that a lot of folks dismiss the round, but they only deal with the subsonic ballistics. I think it can be a very versatile round, especially for reloaders. Kinda like a 357magnum or 10mm.

I’m a huge fan of 300 Blk and shoot it a lot.

It’s basically a better version of an MP5 with subsonic loads and with a change of a mag to SuperSonics, you’re tossing a 30 caliber projectile towards a target at 2,200+ FPS.

Not many guns can do that with a mag change.

I wouldn’t bother with subsonics past 100 yards. You can do it, but that’s not what the subs are really for.

I agree with everything esdunbar said, he pretty much summed up how I feel about 300 blk. It makes people smile when they shoot it suppressed and swap a mag out and shoot a 110 grain projectile at 2100fps.

I only shoot the supers, it's a 7.62x39 that feeds correctly out of a short Bbl AR for me.

I have an 11.3" blk upper. The following is from JBM ballistics at 2,000' density altitude, with the factory loads I have muzzle velocities for. I ran the numbers with a 0" sight-to-bore offset, so true relative bullet drops can be seen. Drops are in MOA, because they get so big for subsonic loads.

Hornady 110 ZMax @ 2395 fps
3.1 MOA -- 100 yards
6.8 MOA -- 200 yards
11.2 MOA -- 300 yards
16.5 MOA -- 400 yards
23.0 MOA -- 500 yards

Sig Sauer 125 HPBT @ 2196 fps
3.7 MOA -- 100 yards
7.9 MOA -- 200 yards
13.0 MOA -- 300 yards
18.9 MOA -- 400 yards
26.0 MOA -- 500 yards

220 SMK @ 950 fps
18.5 MOA -- 100 yards
37.8 MOA -- 200 yards
57.7 MOA -- 300 yards
78.3 MOA -- 400 yards
99.5 MOA -- 500 yards

quote:

Originally posted by hudr:
[I]n the real world.

I’m not certain, but if you’re asking about applications beyond poking holes in paper or banging steel, then your specific purpose is obviously the key to answering your question.

With limited exceptions, shooting suppressed is just for fun. Unless your mission is to take out a sentry or guard dog during a covert operation or hunting silently (rather than effectively), it makes far more sense to use full power, supersonic loads.

As fritz points out, subsonic loads have rainbow-like trajectories that make hitting targets at anything other than short ranges very difficult—and that’s assuming it’s even possible with one’s gun and sight. But that’s not all. If one is trying to inflict damage on the target, a subsonic 220 grain bullet has about the same energy as the 45 ACP, and in my (admittedly limited) testing, few bullets suitable for subsonic 300 Blackout loads expand at their low velocities.* The 45 ACP may be a good handgun cartridge, but it’s a pipsqueak in a long gun.

For normal hunting or defensive purposes I can’t imagine using anything other than one of the good supersonic loads.

* Hornady has just released a subsonic 300 BLK load that they claim will expand. I received a few boxes yesterday, but haven’t had a chance to test them yet.

Fritz’s data is helpful.
“Real world” will include shooting steel and paper, and may very well extend to deprecating my property of feral hogs. I can see suppression being beneficial for that, unless I have to get danger close.

I wonder how subsonic 300blk would be for home defense? It may have the ballistics of 45ACP, but you’d have 30 of them....

The Hornady ammo you mention has me intrigued. Please post your findings

I have to admit....I already have a PSA 300blk pistol that I have yet to fire.
I have recently gotten into a local pistol caliber carbine competition and I have spent my range time behind my 9mm AR pistol

Another thing to be aware of with rainbow trajectories at longer ranges is how critical range determination becomes. Assume we’re firing the 220 grain Sierra MatchKing at 1000 feet per second from a typical AR and with 100 yard zero: If we believe the target (a hog’s head, for example) is 200 yards away, but it’s actually 190 or 210 yards, we will be high or low by about 5 inches. If the target is estimated to be at 300 yards, but it’s actually at 290 or 310 yards, we’ll be high or low by about 9 inches—sufficient to cause a complete miss of even a hog’s body.

As for home defense, as I’ve opined many times before, any projectile from any gun will usually be good enough. But what if it’s not good enough? Every choice we make about self-defense guns and ammunition involves compromises, and therefore we must choose the best we can. We don’t, however, have to always choose to limit ourselves in all things.

If I have a long gun available for the purpose, I would not choose to limit myself to handgun ballistics. I may have 30 rounds available, but my assumption is always that things will not go as well as I hope; as a friend points out, hope is not a strategy. If I must shoot someone, it’s because he poses a deadly threat, and that means he probably has a gun himself and is about to shoot at me, or is already shooting. Even unskilled shooters can fire some guns very quickly, and therefore my best chance of avoiding death or serious injury is to make him stop as soon as I can. The difference between a hit that causes a lot of damage and a hit that causes less damage may be enough to permit one’s adversary to get off the shot that causes me damage.

If I ever decide to use a gun chambered for 300 Blackout for serious purposes (other than taking out that sentry), it will be loaded with serious ammunition, and not ammunition intended to make the spectators to go, “Ooh” and “Ah!” because of how quiet it is.

I built a 300 Blackout to be used as a subsonic home defense gun until I learned how poor the ballistics are. Now I use suppressed supersonics for HD and subs are for plinking at the range.

How do the two compare? At 200 meters both can hit 4" steel with plenty of accuracy. There is no question observing the difference in energy between the two. The drop is significant. I don't know the numbers off the top of my head but my Romeo 4 is sighted for suppressed supersonic and when switching to suppressed subsonic I have to center the target about 2/3rds down between the center dot and the bottom of the circular reticle.

At the 200 meter range there are dueling trees with 4" plates. One guy had a .308 AR-10 and the best way I can describe the difference in energy is that the subsonic 300 BO was like turning a page, the supersonic 300BO was like closing a book quickly and the AR10 was like throwing the book across the room.

300 bolt shooting subs for critters that try to get my critters at night. His and her AR pistols shooting suppressed subs for hearing safe home defense. Shoulder mounted accuracy with 30 rounds of angry 45 energy in a weapon that is harder to take away at close distances. We each keep a 20 round mag of 110 gr supers with our kit in case it develops into a longer situation but if we have that much time we have better tools...

Seems to work well for us.

Mark

Subsonic ballistics aren’t poor at all imo.

To be subsonic, a round had to travel under 1,000ft/s-ish. You’re never going to get rifle ballistics at that speed. Subsonic by nature is not rifle ballistics. A 556 subsonic is basically a .22 LR.

What you do get in a 300 blk subsonic is the same bullet weight as a .45 but with a lower cross sectional density and more streamlined shape; both offering better penetration.

It will transfer a good bit of energy into a critter for sure. My home defense gun is suppressed 300 blk, and I have the first 10 rounds subsonic. The next 20 are super.

If I’m 10 rounds into an issue, I won’t mind a few added decibles.

I haven't heard many older vets complain that a Thompson was underpowered. I have heard that Vietnam vets liked having a Thompson for CQB work, if they could get one.

With all the excitement over MP5 clones, Scorpions, and MPX's in 9mm, a 45 ACP equivalent (bullet weight and speed) that can be used in a standard AR with little more than a different barrel and maybe a buffer weight change should be a winner.

Now add to that the option of AK performance (weight/speed) if you want it and I think you have a slam dunk.

The question isn’t whether a cartridge is “underpowered,” the question is whether it’s possible to get more power with the same gun. In the case of weapons chambered for 300 Blackout, that couldn’t possibly be more true: Supersonic loads have more power and therefore the ability to do more damage to the target than subsonic loads. A 220 grain bullet at 1000 feet per second produces 488 foot-pounds of energy; a 125 grain bullet at 2200 fps produces 1343: almost three times as much. If I’m ever shot with that cartridge, I hope it’s with a handgun ballistics load.

Regarding military anecdotes, there was a tendency for personnel in areas like Viet Nam to romanticize weapons they weren’t issued and couldn’t get. The Thompson was rare and therefore desirable for only those reasons. The M3 submachine gun, however, fired the same 45 APC cartridge and was neither. (I even had one myself, but even then I knew enough about guns and ballistics to rely on my M16 for serious purposes.) To cite a contrary example, a more desirable weapon—also among rear area types—was the German MP40 despite the fact that magazines and ammunition were hard to come by and the 9mm Luger cartridge was less powerful.

This message has been edited. Last edited by: sigfreund,

To elaborate on why I chose super vs. subsonics in my HD setup, the two key differences were JHP vs. FMJ and the triple energy factor sigfreund stated. Perhaps things have changed as I haven't kept up with it but a few years ago all the 300 Blackout subsonics SD loads I found were FMJ. While comparable to the .45 in weight, speed and energy, I think we can all agree that JHP is the preferred self defense bullet for ballistic purposes. While the subsonics are pellet gun quiet, shooting supersonics through a suppressed 8.2" barrel wasn't hard on the ears at all and is much more preferable than an unsuppressed pistol.