Topic Dead

[HB]

300BLK is the better suppressor host of course, those SubSonic rounds were specifically made for the task, and that is why the military adopted it

Does the military actually use 300 Blackout?

I would like the know the ratio of 5.56 guns to other calibers in civilian hands, and also in military inventory. I am also extremely skeptical that anybody in uniform has ever changed mags from subsonic to supersonic in the course of duty.

I don’t find either useful. I have better rifles for hunting. I like my ARs as varmint rifles/sub 400 yard steel shooters. If I was restricted to one rifle and I didn’t hunt much, I may consider a grendal.

 

[MechaDragon]

Does the military actually use 300 Blackout?

I would like the know the ratio of 5.56 guns to other calibers in civilian hands, and also in military inventory. I am also extremely skeptical that anybody in uniform has ever changed mags from subsonic to supersonic in the course of duty.

I don’t find either useful. I have better rifles for hunting. I like my ARs as varmint rifles/sub 400 yard steel shooters. If I was restricted to one rifle and I didn’t hunt much, I may consider a grendal.

Yes the military is actively using 300 Blackout right now. However they don't use it in the same way civilians use it. Civilians usually build a 9 to 10 in blackout gun so that it's more universal And can use supersonic rounds. However that doesn't make sense because even 300 Blackout supersonic rounds are pretty horrible in terms of efficiency, bullet drop, and effective range.

The military exclusively uses 300 Blackout for covert operations with the subsonic rounds suppressed to be extremely quiet and sneaky and hit enemy soldiers at up to 200 yds away and still drop them. That's exactly why it's the replacement for 9 mm SMGs.

So where civilians are screwing up, is assuming that the cartridge is a universal platform, but it isn't really.

Meanwhile 6.5 Grendel is being used in the Serbian military CORRECTLY as a universal cartridge that works out of both short barrels and longer barrels effectively at medium ranges for short barrels and longer ranges for longer barrels.

So as usual it's just the civilian mindset that doesn't seem to understand military intent.

So let's just take two different scenarios as examples. In the first scenario, military personnel needs a sneak around at night making as little noise as humanly possible taking down enemy soldiers hiding out in buildings or out in the forest. The objective is to sneak up on them and put them down without anybody you ever knowing. 300 Blackout with a very short barrel and a suppressor with subsonic rounds is what will be used for that mission.

For a general firefight in a city where stealth is not prioritized and you need a capable round in a compact package that can deal with both combat indoors and outdoors, then the military goes with our new squad weapon - the Sig Spear in 6.8x51mm otherwise known as the 277 Fury.

And trust me, you don't want to be a civilian trying to use 277 Fury as your go-to rifle. Mainly this is because 277 Fury is a cartridge that basically uses a modified 308 casing. So you have stepped up from an AR-15 to an AR-10. It is an extremely powerful partridge with extremely high velocities and extremely high ballistic coefficiences as well, but it kicks similar to a 308 because the cartridge was based on a 308. And if you're a soldier train in the military that's going to be fine for the most part, but as a civilian that kick is going to be too much for rapid follow-up shots for a lot of people.

And that's before we talk about ammunition costs and 277 Fury is expensive as all hell. The very cheapest ammunition you can even find right now is $1.25 per round.

 

[jmorris]

Does the military actually use 300 Blackout?

"Military use
Although no cartridge has been accepted as such by any military, certain special force units have taken it into use."

.300 AAC Blackout

The .300 AAC Blackout (designated as the 300 BLK by the SAAMI and 300 ACC Blackout by the C.I.P.), also known as 7.62×35mm is a rifle cartridge developed in the United States by Advanced Armament Corporation (AAC) for use in the M4 carbine. Its purpose is to achieve ballistics similar to the...

military-history.fandom.com

They wanted to use an unmodified 5.56 BCG and mags and not loose capacity, the 6.5g doesn't allow for any of that.

I can't say thats actually a bad thing, at least not as bad as a .300 firing in a 5.56 rifle....pretty destructive.

They didn't have either when they CQB'ed at bin laden's place, choosing 5.56's instead, out of short barrels.

 

[MechaDragon]

"Military use
Although no cartridge has been accepted as such by any military, certain special force units have taken it into use."

.300 AAC Blackout

The .300 AAC Blackout (designated as the 300 BLK by the SAAMI and 300 ACC Blackout by the C.I.P.), also known as 7.62×35mm is a rifle cartridge developed in the United States by Advanced Armament Corporation (AAC) for use in the M4 carbine. Its purpose is to achieve ballistics similar to the...

military-history.fandom.com

They wanted to use an unmodified 5.56 BCG and mags and not loose capacity, the 6.5g doesn't allow for any of that.

I can't say thats actually a bad thing, at least not as bad as a .300 firing in a 5.56 rifle....pretty destructive.

@HB This pretty much says it right here, because it's a specialized cartridge best suited for cover operations at extreme stealth, it is only used by special operations units that sneak around and take out the bad guys without making a sound which is pretty much exactly what I said in my last reply except that I also explained why the main infantry in an actual firefight would use the new 277 Fury squad weapon instead of doing what civilians do with 300 Blackout which is just try to equip a longer barrel that can fire supersonic rounds with a little more efficiency.

That extra efficiency from a 9 or 10-in build for 300 Blackout supersonic does make the platform overall more versatile, but that doesn't mean it's actually GOOD at being versatile, because it really isn't.

 

[Savage30L]

This is one of the most interesting discussions I've seen on THR. I, too, have wondered why the 6.5 Grendel isn't more popular, as it has always struck me, "on paper", as the pinnacle of intermediate-cartridge development. But there are so many practical considerations.....all of the points brought up here are valid. Kudos to all of the contributors.

My two cents:

I think the comments about the Serbian firearm are on the right track. What ought to have been done (for this cartridge to catch on), would have been to design a new carbine (and magazine) specifically around the cartridge. Bureaucratic inertia, lack of lobbying dollars, and cost were presumably insurmountable.

I have never been a fan of the AR platform. I've never bought one because I see the AR as the Taylor Swift of the firearms world. While I do get that its huge popularity has paved the way for modularity and inexhaustible accessory options, its original design left a lot to be desired. I detest direct impingement guns. And a lot more about the design concept, but I'll stop here so as to stem thread drift.

We also can't overlook marketing failure. Why did the 6.5 Creedmore spread like wildfire, while the .260 Remington barely hangs on?

 

[MechaDragon]

@Savage30L Well I can say with utmost certainty that you get it. That you completely understand why 6.5G should be pushed harder.

I too don't like DI guns all that much, I was first looking into CMMG Dissent 300BLK guns because the bufferless design allows for shooting while being more compact. The buffer tube on standard DI system ARs is my biggest gripe with them.

However, if that system allows me to shoot 6.5G in a short package then I suppose I can overlook that issue. CMMG missed the mark by not offering a Dissent 6.5G in a shorter barrel such as 10.5, 11.5, or 12.5" variations. If they had, they would have had a sale from me personally.

From here, there is only one real option: Alexander Arms 11.5". 6.5G is his design anyway so performance should be as optimal as possible.

 

[westernrover]

Speaking of which, I actually have an idea of how to create a round that is more similar to 556 and 300 Blackout by using the original 556 case and therefore retaining magazine capacity which is one thing that Grendel does not have because it's fatter case means less magazine capacity - and use a projectile in between that of the 556 and the 300 Blackout that is specifically focused on aerodynamics and high ballistic coefficients to create a cartridge similar to Grendel incapability but costs much less to produce because of the 556 case.

For example, why not take the 556 case and neck up just as they did with 300 blackout, except instead of a big fat projectile, more of a medium projectile That is very pointy and aerodynamic like the Grendel projectile, just a bit smaller and lighter overall. This ideal projectile would have a grain weight typically around 80 grains at the lightest point and 110 or 120 grains at the heaviest point. Hunting rounds would typically be 95 or 100 grain with tips similar to the Hornady SST or Black series.

It's been done. The 6x45 is the 24 cal, the 25-45 Sharps is 25 cal, the 6.5x45 is the 26 cal, the 6.8x45 UCC is the 27 cal, the 7mm TCU is the 28 cal, and the 300 HAMR is the 30 cal... and it keeps going.

 

[westernrover]

@HB This pretty much says it right here, because it's a specialized cartridge best suited for cover operations at extreme stealth, it is only used by special operations units that sneak around and take out the bad guys without making a sound which is pretty much exactly what I said in my last reply except that I also explained why the main infantry in an actual firefight would use the new 277 Fury squad weapon instead of doing what civilians do with 300 Blackout which is just try to equip a longer barrel that can fire supersonic rounds with a little more efficiency.

I have a strong feeling that you don't actually have any experience with any of these guns. It's ok to ask questions and begin to understand these things. You will learn more if you begin with the premise that you don't know and that a lot of what you read on the internet is written by people like you.

 

[westernrover]

The reason for not going 6.8 ARC is simple: The cartridge has basically dropped off the map, it has almost no popularity and no following by hardly anyone. Weirdly enough, Grendel has been picked up not only by the Serbian military, but also here in the States as a popular hunting round for a medium game such as deer because of its insanely good ballistic properties. Out of a full-blown 18-in hunting rifle, Grendel has the power to hold ethical kill energy for deer out to 400-450 yards. I know that doesn't seem possible out of an AR-15 sized platform but it is because the best rounds have a ballistic coefficient around or just above 0.500. Grendel is simply the most capable cartridge available until you step up to a larger AR-10 platform with cartridges related to the 308 Winchester.

The 6.8 SPC has dropped, but it contended with the Grendel for something like 15 years. The Grendel is coming close to being next to drop like that. The 6mm ARC has become more popular than 6.5 Grendel at this point, simply because it's newer and that prompts marketers to generate more hype. It does have advantages compared to the 6.5. There really is no reason for any of these cartridges not to be popular or have a following. Each of them do everything you claim. The only one I have myself is 6.5 Grendel and the reason for that is because that's what makers were chambering (what was the hot hype) at the time I bought the rifle back in 2018. If I were to go looking for a bolt-action rifle now, I would probably find a 6mm ARC easier -- and I wouldn't have any reason not to choose that instead.

 

[westernrover]

This ideal projectile would have a grain weight typically around 80 grains at the lightest point and 110 or 120 grains at the heaviest point. Hunting rounds would typically be 95 or 100 grain with tips similar to the Hornady SST or Black series.

Why not just load an 80 or 90-grain projectile in 5.56x45 and be done?

 

[MechaDragon]

The 6.8 SPC has dropped, but it contended with the Grendel for something like 15 years. The Grendel is coming close to being next to drop like that. The 6mm ARC has become more popular than 6.5 Grendel at this point, simply because it's newer and that prompts marketers to generate more hype. It does have advantages compared to the 6.5. There really is no reason for any of these cartridges not to be popular or have a following. Each of them do everything you claim. The only one I have myself is 6.5 Grendel and the reason for that is because that's what makers were chambering (what was the hot hype) at the time I bought the rifle back in 2018. If I were to go looking for a bolt-action rifle now, I would probably find a 6mm ARC easier -- and I wouldn't have any reason not to choose that instead.

Makes perfect sense in a bolt action, but Im looking for what a lot of the 300BLK community is looking for - a short barreled semi-automatic that can still produce results at hunting ranges.

Thats precisely why 6.5 Grendel grew in popularity as a hunting cartridge. Thats why theres an entire website called "Grendel Hunter" that specializes in making custom lower receiver builds for the 6.5G cartridge and offers many other parts as well.

Why not just load an 80 or 90-grain projectile in 5.56x45 and be done?

They have already done that. Its 25-45 sharps. The issue with those is they are designed with longer barrels in mind and don't even offer a barrel shorter than 16". The powder is also standard and not fast-burning. Although, you could potentially modify the cartridge with newer powder to do so.

 

[Lennyjoe]

I built an AR in 6.5 Grendel but after building another one in 7.62x39, I sold the Grendel.

 

[westernrover]

I think you'll find that a short barrel ruins the ballistics of bottleneck cartridges and any small-bore cartridge period. There is no magic. It's physics. When you get to handgun barrel-lengths 10 inches or less, there is a reason that handgun cartridges tend to forgo bottleneck cases and almost invariably go to big-bore (greater than 40 cal) to get more performance. You don't see many hunting handguns in bottleneck cartridges, not even BFR or S&W X-frame where they could fit, because they don't work in short barrels. Even with the Contender or XP-100, they're not popular because they don't work. Also, consider the 300 BLK for example, and notice that it's practically a straight-wall cartridge, but sucks compared to 360 Buckhammer or 400 Legend from short barrels. The fact is, for shorter barrels, moving up in caliber is the key to performance, not moving down. Look at the 458 SOCOM. The trade-off, of course, is long-range performance. If you want to understand the 300 BLK, realize that it's the middle compromise. It's not the best or even particularly good at either, but it straddles short-range subsonic performance and long-range supersonic performance -- you could think of it as the worst of both worlds, but it is in both worlds.

For long-range performance, I can't think of any cartridge that will not demand a long barrel. There is no way, within the limitations of conventional firearms cartridges, to accelerate a bullet to high enough velocity within a short barrel. Bullets are accelerated by pressure behind them over time. We're practically limited to something like 80,000 psi MAP (and then only with steel-based cases, ie 277 Fury), and given that pressure limitation, there needs to be sufficient time for that pressure to accelerate the bullet before the base exits the muzzle. A short barrel does not provide enough pressure-over-time. If we use lighter bullets that accelerate in less time, they tend toward low ballistic coefficients and lose all their velocity to drag in a short distance. If we use higher BC bullets, they tend to be heavier and take longer time and therefore longer barrels to accelerate to high velocity. The brass cases are nothing but gaskets to hold the pressure in the chamber. There is no size or shape or name on the brass gasket that is going to change the equation that accelerates a bullet over time.

 

[BreechFace]

I built an AR in 6.5 Grendel but after building another one in 7.62x39, I sold the Grendel.

Larger bore, gets the projectile up to speed quicker and more efficiently; same for 300 BLK but the case capacity of x39 really shows up especially when loading to CIP and using CFE BLK. The x39 really gets life breathed into it when one handloads

 

[MechaDragon]

@westernrover That's exactly why 6.5G is so special. Its one of the few Cartridges, in fact the ONLY one in the smaller AR15 platform that can take a short barrel and still reach out to longer distances.

Although the Humane Kill energy drops off after about 250 to 300 yards, It is a very accurate cartridge even from a short barrel up to 750 yards. People have actually taken the 11.5 in Alexander Arms 6.5G and hit steel at 1000 yards. What other platform can you honestly think of that could even achieve that?

And for those of you wondering, 277 Fury in the military is actually 6.8x51mm And that's not just the name change, The loading is actually different. If you want to see how different and why the military one is so special, watch this video. It features one of the only people in the world who have actually gotten to try the real military ammunition or at least the same muzzle velocity:

Shots Fired 277 Fury & 6.8 x 51

Deals and other cool finds https://linktr.ee/alabama_arsenal"This video is for educational and entertainment purposes only. All guns displayed off the range...

youtu.be

 

[BreechFace]

@westernrover That's exactly why 6.5G is so special. Its one of the few Cartridges, in fact the ONLY one in the smaller AR15 platform that can take a short barrel and still reach out to longer distances.

Although the Humane Kill energy drops off after about 250 to 300 yards, It is a very accurate cartridge even from a short barrel up to 750 yards. People have actually taken the 11.5 in Alexander Arms 6.5G and hit steel at 1000 yards. What other platform can you honestly think of that could even achieve that?

How about 750m from what appears to be about a 7-8" 300 Blackout AR and red dot?

Others have pushed that out to 1,000 yards, I'll have to find that video. Knowing holds and a good shooter and equipment a lot can be accomplished.

Skip to 6:30-7:40 for the 750m target.

300 BLACKOUT YEAR

Travis talks about HSP's year in 300 Blk Out. He also takes to opportunity to discuss their findings and explain their justification of the round as a multi...

www.youtube.com

 

[Jim Watson]

They have already done that. Its 25-45 sharps. The issue with those is they are designed with longer barrels in mind and don't even offer a barrel shorter than 16". The powder is also standard and not fast-burning. Although, you could potentially modify the cartridge with newer powder to do so.

A barrel shorter than 16" gets you into the SBR/NFA bureaucracy. Why would I want to do that?
What is the advantage of "fast-burning" powder?
What "fast-burning" powder does a low expansion ratio cartridge like 6.5 Grendel use?

 

[westernrover]

@westernrover That's exactly why 6.5G is so special. Its one of the few Cartridges, in fact the ONLY one in the smaller AR15 platform that can take a short barrel and still reach out to longer distances.

No, it doesn't. It doesn't develop the velocity in a short barrel, and it doesn't have any magical properties. It's not special. Besides, whatever it can achieve in a short barrel, could also be achieved by several of the other similar cartridges that have already been mentioned. The only reason Grendel isn't just as obscure as 375 SOCOM or 30 Remington AR is because Hornady decided to pick it up and promote it, but they've moved on the 6mm ARC that shoots faster and flatter.

 

[jmorris]

I have never been a fan of the AR platform. I've never bought one because I see the AR as the Taylor Swift of the firearms world.

Hmm, never made that connection. Then again, I've had them since before she was born...

 

[MechaDragon]

How about 750m from what appears to be about a 7-8" 300 Blackout AR and red dot?

Others have pushed that out to 1,000 yards, I'll have to find that video. Knowing holds and a good shooter and equipment a lot can be accomplished.

Skip to 6:30-7:40 for the 750m target.

300 BLACKOUT YEAR

Travis talks about HSP's year in 300 Blk Out. He also takes to opportunity to discuss their findings and explain their justification of the round as a multi...

www.youtube.com

Oh yes I have seen similar videos and yes it is impressive that 300 Blackout can hit 750 m however that's with extreme drop and on top of that it has basically zero energy remaining. Even the very best blackout load loses the ability to cleanly and ethically kill a deer at about 150 yards from a 10 or 11-in barrel. Because 6.5G has a much higher ballistic coefficient than 300 blackout, a shot from the same length barrel around 10 or 11 in retains its ethical killing power out to 250 or 300 yd.

On top of this, it experiences much less drop. The closest comparison in ballistics charts that I can find was 300 Blackout versus 6.5 Grendel fired from a 16-in barrel. In these charts, the 300 Blackout was a 110 grain and the 6.5 Grendel was a 115 grain so you would expect the blackout to have a slide advantage with a slightly lighter projectile, but Grendel walked all over the blackout. At 500 yd, 110 grain blackout only has about 360 foot pounds of energy left and has dropped about 86 in. Grendel at 500 yd still has about 675 ft pounds of energy and has only dropped about 58 in. In this particular test, both weapons were zeroed at 200 yards. That is the power of a more aerodynamic projectile with a higher ballistic coefficient as a result.
From a 16-in barrel, Grendel can hold about a thousand foot pounds of energy out to 300 yd which is very, VERY impressive. And because the overall casing is fairly short it doesn't lose an absolute ton of velocity when shortening the barrel, quite like 300 Blackout.

A barrel shorter than 16" gets you into the SBR/NFA bureaucracy. Why would I want to do that?
What is the advantage of "fast-burning" powder?
What "fast-burning" powder does a low expansion ratio cartridge like 6.5 Grendel use?

Actually it doesn't necessarily mean you have to deal with NFA. The pistol brace issue is basically over. It is now legal to have a two-handed firearm with a barrel shorter than 16 in and have a pistol brace on it and not register with the NFA.

The advantage of faster burning powders is that the projectile can accelerate closer to maximum velocity out of a shorter barrel therefore giving you a more compact weapon with a capability closer to a full size weapon.

 

[MechaDragon]

No, it doesn't. It doesn't develop the velocity in a short barrel, and it doesn't have any magical properties. It's not special. Besides, whatever it can achieve in a short barrel, could also be achieved by several of the other similar cartridges that have already been mentioned. The only reason Grendel isn't just as obscure as 375 SOCOM or 30 Remington AR is because Hornady decided to pick it up and promote it, but they've moved on the 6mm ARC that shoots faster and flatter.

I never claimed that it was a magic bullet or that it has no advantage going with a longer barrel because it does. But because of its insanely good ballistic coefficient, you can get ethical deer kill out to 250 to 300 yd from an 11.5 in barrel.

That ethical kill range is extended to more like 400 to 450 yards with a 16-in barrel. So yes, it clearly gains a lot from a longer barrel, but it's so effective from a short barrel that it handily out classes 300 Blackout in a short barrel.

 

[westernrover]

However, despite the higher price of ammunition now, it still doesn't actually make that much sense because back before the price hikes 6.5 Grendel was actually about the same price as 556 because the casing is quite similar to the 762x39.

Even though 556 was also cheaper before the price hike, the difference is that Grendel was also about the same price as 556. I can understand the price of both rounds going up at a similar pace thanks to said political issue that caused prices to skyrocket. But now that both rounds have gone up in price, Grendel has ended up twice as expensive as 556.

5.56x45 has never been more than half what Grendel was at the same time. There has never been anything like parity in their cost. The scale of 5.56x45 production has always dwarfed 6.5 Grendel, and the only way 7.62x39 was ever as cheap as 5.56x45 was because of cheap steel-cased ammo imported from countries in economic shambles. Those countries never produced 65 Grendel.

They have already done that. Its 25-45 sharps. The issue with those is they are designed with longer barrels in mind and don't even offer a barrel shorter than 16". The powder is also standard and not fast-burning. Although, you could potentially modify the cartridge with newer powder to do so

You don't handload do you? It seems like you're just running a keyboard writing about this mythical SBR in your imagination, but you have no experience with SBR's in any chambering, no experience with handloading 6.5 Grendel or any other AR intermediate cartridge, and I doubt that you even have any substantial experience with a standard AR in the most common barrel length and chambering.

If you want an SBR in an unusual chambering, they're built using custom barrels. What's "offered" doesn't matter. You can't expect to get the best performance without handloading. Factory ammunition isn't going to be suited to short barrels. It will be produced with powder and bullets optimized for the great majority of non-NFA item consumers that are shooting them at higher velocity than will ever come out of an SBR.

You would be so much better off getting experience with a 16" AR in 5.56x45 than wishing for the world to make something different more popular. If you want an SBR, get one without trying to re-invent the wheel. You'll have enough to do just to acquire a regular one without unicorn features. Start handloading. Get those three things together and you'll know a lot more than you do now and you'll be able to make a lot better decision about what's really needed.

 

[someguy2800]

I disagree with your premise because defending yourself at 300 yards with your SBR as a civilian in the United States is so incredibly unlikely as to be basically a fantasy. I would say the majority of people that see 300 blackout as a good defensive option are thinking in the context of inside their home, perhaps the length of their front yard. In that context the only thing 6.5 grendel gives you is more recoil, more sight disruption, more blast, less magazine capacity for a given length, and less reliable feeding and extraction. No thanks, I'm good.

I suppose if I really needed to try to find a cartridge that I needed to defend my family with AND go deer hunting with at more than 200 yards I could see some merit to the grendel over 300 blackout, but I don't need to have just one rifle for both. Even if I did have some desire to do both with one rifle I wouldn't pick either of them.

 

[someguy2800]

I am trying to remember but I believe AAC 110 gr Vmax did 2450 from my 14" 300 blk so no you don't need a 16" barrel for that.

 

[Jim Watson]

Actually it doesn't necessarily mean you have to deal with NFA. The pistol brace issue is basically over. It is now legal to have a two-handed firearm with a barrel shorter than 16 in and have a pistol brace on it and not register with the NFA.

1. I don't think the chance of restrictions on the "pistol brace" gimmick is over.
2. I don't want a "pistol brace" or, for that matter, a real SBR, but that is a matter of choice and application, it's your money.

The advantage of faster burning powders is that the projectile can accelerate closer to maximum velocity out of a shorter barrel therefore giving you a more compact weapon with a capability closer to a full size weapon.

No.
It has been well demonstrated that maximum velocity in any barrel length comes from a combination of maximum chamber pressure and maximum case fill, which is pretty much the definition of slow burning. That will also lead to higher port pressure and higher muzzle pressure but hey, you have an adjustable gas system and a silencer, don't you?