quote:

Originally posted by copaup: BC, Ballistic Coefficient. That projectile weighs about the same as a 45 acp, but is moving faster and is more efficient.

That’s the same reason that subsonic .300blk goes through bulletproof glass, vs a pistol round (9mm, .40S&W, 45ACP) traveling at the same or similar speed being stopped in its tracks. It certainly has its ballistic advantages.

Here’s my 8” .300blk SBR.

Aside from 10mm, I've never been a fan of "wildcat" calibers.

300blk is here to stay, and belongs with short barrel and suppressed applications. Heavy bullets.

Heavy bullets deliver.

Newer to 300 BO. I'm looking at getting some HD and range ammo for my unsuppressed 10.5". Should I be looking at subsonic? Any specific rounds?

Thanks.

If you're not using a suppressor, there's no need to stick to subsonic ammo.

Whether shooting suppressed or unsuppressed, my personal preference would still be a heavier bullet.

quote:

Originally posted by RogueJSK:
If you're not using a suppressor, there's no need to stick to subsonic ammo.

Yep.

Wasabi...

The slow muzzle velocities of 300 blackout loads means that 30-cal bullets designed for 308 Win or 300WM don't expand as much in a blackout load. A 200-220 grain match-type bullet may not expand, tumble, or fragment. The 110 grain Vmax can be expand explosively at 308 velocities, but expands more reasonably in a blackout. 140-150 grain FMJ bullets in blackout can look pristine after being fired into dirt or sand -- almost good enough to reload.

Kinetic energy is another consideration. My blackout barrel is 1" longer than yours, but your relative values will be similar.
I see muzzle energy (ME) of around 1350 foot pounds with 110 grain loads.
MEs from the 125s range from 1240 to 1350 foot pounds.
MEs from 140-150 grain loads in the 1200 to 1250 ballpark.
The subsonic 190-220 grain loads I've shot are in the 550-600 foot pound area.

IMO Hornday 110 Vmax is a decent round for HD, and it's accurate to at least 400 yards at the range.
If you're looking for a lead-free bullet, the Barnes 110 and 120 Vortex rounds are worth a look.
A 125 grain plastic tip is a possibility. Think Fiocchi 125 SST.

Many of the subsonic heavy loads have bullets that don't expand at subsonic speeds. If I had no options for supersonic ammo, I'd probably choose Hornady Sub-X 190 for HD.

I can see two niches for it: subsonic loads for use with suppressors, and hunting deer-sized game when a heavier bullet is wanted or to comply with state laws that prohibit .22 caliber for such game. Neither are applicable to me.

quote:

Originally posted by arcwelder:
Aside from 10mm, I've never been a fan of "wildcat" calibers.

How is 10mm a wildcat caliber?

I bought a 300 BO upper a few weeks ago and got to shoot it over the holiday weekend. Mine is a 10.5 barrel and I was using an AAC 7.62 CAN with 200 grain ammo. I actually thought it was louder than what I had hoped. I'm going to try some heavier ammo, but so far I am not sure I'll keep it.

quote:

Originally posted by walker77:

quote:

Originally posted by arcwelder:
Aside from 10mm, I've never been a fan of "wildcat" calibers.

How is 10mm a wildcat caliber?

Well it’s metric for one.

quote:

Originally posted by MikeinNC:

quote:

Originally posted by walker77:

quote:

Originally posted by arcwelder:
Aside from 10mm, I've never been a fan of "wildcat" calibers.

How is 10mm a wildcat caliber?

Well it’s metric for one.

9x19
7.62x51
7.62x39
5.56x45
7.62x54
7 Remington Mag
7x57 Mauser
I suspect a few aren't wildcat. I know there are a bunch of metric rifle cartridges used for foreign countries. A few must be original calibers.

For the many years extending back decades when I got most of my information about guns and shooting from the periodicals, “wildcat” was always used and understood to refer to cartridges that were not offered by major ammunition manufacturers and major firearms manufacturers didn’t offer guns chambered for the cartridge. In fact, this is what the 11th edition of the book Cartridges of the World has to say about the term:
“[C]artridge designs and loads not available from major manufacturers as over-the-counter ammunition or cartridges not generally available even in custom loadings.”

Once a cartridge moved out of that category, no one I ever saw continued to refer to them as a “wildcat.” “Former wildcat” or “started as a wildcat,” yes, but they were recognized as having made the transition, even if they were not common. And of course, no one referred to old, obsolete cartridges as wildcats if those criteria were met at one time, such as all the straight wall black powder rounds that were once common. And no military round was ever referred to as a wildcat.

Of course, once someone starts using a term in a way that changes its original meaning and that misuse becomes common, then that’s another story. I’ve noticed that gun owners and shooters are especially prone to doing that. If enough people start using “wildcat” to refer to a cartridge because they don’t own a gun that fires it, then it will become another old term whose meaning has changed markedly.

I’ve been thinking about the original question and to offer an opinion, yes: I believe the 300 Blackout is worthy of serious consideration for specific applications. I’ve already mentioned a couple of points about the round, but there are other, and perhaps more important considerations.

There are countless cartridges whose performance and other characteristics are very similar to each other.
At most they vary slightly in maximum velocities possible and the bullet weights they can use effectively while offering advantages (or suffering disadvantages) in action size, reputation for inherent precision, and barrel life, to name the most obvious. They all have their fans, but the absence of many common cartridges would result in no noticeable ballistic performance gaps if they had never existed because there are so many others that don’t differ much in significant ways.

I don’t believe, though, that that applies to the 300 Blackout. It’s a cartridge with limited applications, but for those applications it seems to me that nothing else offers its specific characteristics in similar guns.

One oft-mentioned claimed exception to that generalization is the 7.62×39mm Soviet cartridge that’s beloved by countless AK fans. But which is better, the 7.62 or 300, once we’ve settled on wanting their general physical and performance characteristics? The second part is easy to answer: Their ballistic performance is very similar when loaded with similar bullets. That, however, runs into the question of how similar are the bullets that the two are—and can be—loaded with?

Despite its designation, the old Soviet round is not normally loaded with 0.308 caliber bullets and therefore available choices are far more limited even for the handloader. Bullets that will fit the 300 BLK, however, are among the most common. So, that’s one consideration.

Then there’s the 300 Blackout’s suitability for being loaded to subsonic velocities. That’s not something that interests me very much, but it matters to many shooters.

More important, IMO however, is the case design of the two cartridges. I understand that the more tapered case of the 7.62 makes for more reliable chambering and extraction under adverse conditions, especially with steel cases. If that’s a genuine concern for someone, then that settles the question for them. But for most of us? Nah. The 300 Blackout case is very similar to that of the 5.56/223 and those cartridges have been conclusively demonstrated for decades to permit reliable feeding, chambering, and extraction with a modicum of proper weapon maintenance. The 300 BLK obviously doesn’t have that lengthy track record, but absent evidence to the contrary, I will rely on that piggybacked assumption.

And once we get past the need for a cartridge case shape that demands a radically-curved magazine, then there’s the case size. Being smaller in diameter, the 300’s case permits loading the same number of rounds in a significantly shorter and much less curved mag—or not curved at all. Both factors make for easier, more compact storage and carry. I don’t have any experience with what some people would call “banana clips,” so I don’t know if their shape is any disadvantage for quick, efficient reloads, and I suppose it’s a matter of practice, but at an intuitive level a straighter design just seems better.

The greatest advantage of the 300 BLK magazine, though, is that it fits the incredibly common standard AR lower without any modifications. I can swap 5.56/223 and 300 Blackout uppers with no concerns about relying on a single lower for both. And although some 300 loads benefit from magazines designed specifically for the cartridge, most of the time the round feeds and chambers just fine from common-as-dirt 5.56 mags.

Are there other cartridges that fit the niche filled by the 300 Blackout in terms of “shootability” (including low recoil and muzzle blast), power (especially from short barrels), short to moderate range precision, load variety and flexibility, ready ammunition availability, and the ready availability of barrels and uppers? None that I know of. The cartridge isn’t something that every shooter has any use for, but for those of us who do, it indeed is a “worthy” offering that fits its role unlike anything else.

I think its entire viable, and I built one 3+ years ago. In between starting my own business and working in a rifle shop, I had very little free time. I used what little free time I had to think about my job; where it took me, and when. I defined a certain set of parameters to what I wanted with me should I need to go defensive. Lets just say that on the road, in the back waters and on the border you see things, and they ARE NOT figments of your imagination.

My job, then as now, finds me in the boonies in the southern US, and along the border on Tex/Mex. Most of my private customers are gun loving types who wont have a problem with a kitted out 870 or 1301 loaded with slugs in the front seat of my truck. However I have had a few that took offense. My more public customers have tons of signage prohibiting my carry of weapons on their property because they have security or their own actual police (Railroad Special Agents...).

I decided I wanted a weapon capable of 0-300 meters. I wanted the carbine to fire projectiles that could be considered "barrier blind". I wanted a certain capacity in the gun; 20 rounds +/-. Most importantly I wanted it to fit in a lap top bag or in my center console.

At the rifle shop I built a .300Blackout with an 8" barrel. It has a free floating MLOK forend. MicroBest BCG, ALG trigger, Radian ambi selector, and a few other odds and ends. I topped it with an Aimpoint H1 I had laying around. It took a LAW G3M Folder to make it small enough, and no, I cannot fire with it folded.

With 110gr Hornady GMX it will shoot just a hair over 1.25" groups at a-hunnerd. I have no doubts that said bullet will handle laminated autoglass, car doors, or structural members. Out to 300 yards, with said Aimpoint, I can keep all my rounds on a 6" steel plate.

I do question my need for the cartridge from time-to-time. That bugs me. I do think about an effective 7.62x39 offering, like the 123gr SST. In addition to the factory Hornady ammo I have, I have plenty of once fired brass cases and 300 more 123gr SST projectiles. My love of my vz58 has me wondering if I dont sell my .300BLK and go 7.62x39. Maybe I could find one of those vz58 pistols. Hell, as I am typing this I am wondering again.

But yeah, .300BLK was/is a great idea, and is absolutely a worthy cartridge.

I wasn't sold on the 300 BO based on the ballistics I had looked at. It just wasn't that impressive compared to other calibers.

A few weeks ago, however, Dead Air had a demo of their silencers at a local range. I was stunned by how much quieter 300 BO subsonic is than 5.56 supersonic, and how quiet 9mm is suppressed. I also got to watch a guy shoot a SP5 and a P225A and got to shoot a Henry 45/70 lever-action, all suppressed.

I am hooked, and going to be buying several 300 BO suppressed guns as soon as possible.

What I don't get is going with 300 BO for using supersonic rounds.

6mm ARC is a vastly superior cartridge ballistically, from my investigation, in an AR-15 platform rifle. Very close to .308 performance, but not as much recoil.

quote:

Originally posted by AUTiger89:
What I don't get is going with 300 BO for using supersonic rounds.

6mm ARC is a vastly superior cartridge ballistically, from my investigation, in an AR-15 platform rifle. Very close to .308 performance, but not as much recoil.

300BLK Supersonic is more efficient in short barrels, meaning full power 300 will handily outperform 5.56 out of barrels 10" and under.

It's the supreme intermediate SBR caliber.

I would agree for a full size rifle there are far better choices including ye olde 7.62x39. The steel performance is interesting and disappointing for the 300BLK.

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

quote:

Originally posted by DoctorSolo:
300BLK Supersonic is more efficient in short barrels, meaning full power 300 will handily outperform 5.56 out of barrels 10" and under.

And with much less muzzle blast.

As for comparing one cartridge with another, if we need the ability to punch through steel plate, hopefully no one will be astonished to learn that more powerful rounds shooting similar bullets will usually do that better. The 308 Winchester will out perform the 7.62 Soviet and when loaded to maximum capability the 30-06 Springfield will do better than the 308, the 300 Win Mag …, well, we get it.

But while (mostly) avoiding the temptation to repeat that old ridiculous thing about being attacked by steel plates, different cartridges often have different characteristics than just their power. If we’re just interested in one particular characteristic, then choosing the best one becomes easier, but that’s seldom desirable.

And ultimately it’s all a matter of personal choice unless we’re being dictated to by an employer’s policy, legal considerations, etc., then we pays our money and makes our choices. Have no use for the 300 Blk? Then don’t choose it. I have no use for a shoulder fired weapon chambered for 9mm Luger, and therefore I don’t have one.

But to reiterate about the original question: Yes, the 300 Blackout is a valid choice for certain purposes.

A friend is really trying to get me into this cartridge.