.300BLK - Poised to win or doomed to fail?

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Please forgive me if this question has been asked already, but how do the various .300 AAC Blackout bullets out there fare against common bullets in 5.56mm, 6.8mm, and 6.5mm at longer ranges like 300 to 600 yards?
 
It is a great subsonic option. Not really for long reach. Here is the data you requested....

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I'm not Mr. Silvers, but I think it's pretty obvious that the .300 AAC Blackout was not designed to punch holes in paper. It was designed to kill bad guys and preserve compatibility with the AR-15 bolt and magazine.

Consider this energy comparison with a 16" barrel at a distance of 500 yards with a 100 yard zero:

A 77 gr. 5.56x45mm NATO bullet fired at 2,700 fps delivers 412 ft. lbs. of energy and drops 89.2 inches.

A 110 gr. 6.8mm SPC bullet fired at 2,550 fps delivers 560 ft. lbs. of energy and drops 97.69 inches.

A 125 gr. .300 AAC Blackout bullet fired at 2,200 fps delivers 460 ft. lbs. of energy and drops 133.95 inches.

Interestingly, the way I understand it, kinetic energy is a flawed way to measure "knock down power" in cartridge design.

Rarely is momentum mentioned in firearm press. It is an important indicator of incapacitation capability.

Here's an interesting read: http://www.angelfire.com/art/enchanter/terminal.html

You seldom see momentum mentioned in the Gun press, and when it is it is often misunderstood.

One can think of energy absorption (of a target) as Force x Distance, and momentum absorption as Force x Time. Hence, the heavier but slower bullet with the same energy will travel the same distance in the absorbing material, but because of larger momentum, will take a longer time doing it. It will therefore also impart a greater "kick" to the absorber object.

When talking about firearms, Kinetic energy is expressed in terms of "Foot-pounds". 200 ftlbs is theoretically the energy needed to move a one pound weight 200ft vertically off the ground, or a 200lb weight one foot, or a 100lb weight two feet, etc. However, the KE is a scalar quantity, with magnitude but no direction.

To illustrate this, lets consider a 150gr bullet impacting at 2700fps, giving a terminal energy of 2,428 ftlbs. If fired against a 400lb object it should move it 6ft off the ground, or a similar distance if hit from the side. A 200lb object should be thrown nearly 12ft. Obviously we don't see anything like this in the real world. Even if we allow for the friction of the ground and elasticity of tissue, a man or deer hit by such a bullet doesn't move anything like this distance. This is because the movement of an object hit by a projectile is determined by the momentum, not the kinetic energy.

The 150gr bullet has a terminal momentum of 57.8ftlb/sec, which will move our 400lb target back at a speed of no more than 1.7" per sec. This correlates with what we see in the real world. A deer hit by a bullet flinches rather than being thrown several yards.

Now let us compare that bullet to another projectile, a 1lb cannon ball with the same 2,428 ftlbs of terminal energy. This ball would be moving at 395fps, which does not sound much in firearms terms, but is about 269mph. Since the ball weighs a pound, momentum will be 395ftlbs/sec. That should move our 400lb target back at a speed of 11.85" per sec, which sounds credible for a projectile of this weight and speed.

The difference between a 1lb cannon ball and 150gr bullet is obviously extreme. Is what we have seen significant with smaller differences in projectile weights? If we calculate the momentum for two more bullets with the same energy, we get a 200gr at 2338fps giving 66.8ftlbs/sec and a 250gr at 2091fps giving 74.68ftlbs/sec.

Let's compare the momentum of the three examples above (same variables as before):

The 77 gr. 5.56x45mm NATO bullet delivers 17.07 ft. lbs. per second of momentum.

The 110 gr. 6.8mm SPC bullet delivers 23.79 ft. lbs. per second of momentum.

The 125 gr. .300 AAC Blackout bullet delivers 22.98 ft. lbs. per second of momentum.

While at first the difference between the 6.8mm SPC and .300 AAC Blackout seemed like quite a bit (difference of 100 ft. lbs. of kinetic energy), when you consider momentum, the two cartridges are more similar then they previously appeared (difference of less than one ft. lbs. per second of momentum).

As I understand it, if Mr. Silvers chose a smaller bullet than .30 cal, incapacitation capability or "knock down power" would have likely suffered due to the limitations of the 5.56x45mm NATO case and lack of sufficient increase in momentum.

6.8mm SPC got away with increased "knock down power" and flatter trajectory at the expense of incompatibility with the AR-15 bolt and magazine due to a larger case.

With all that said, if your goal is to punch holes in paper, the .300 AAC Blackout is not for you.

If your goal is to kill bad guys, you want more "knock down power", and you want compatibility with the AR-15 bolt and magazine, then the .300 AAC Blackout is for you.
 
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I agree with Ragsdale. Terminal effectiveness cannot be measured in energy alone. Energy alone is meaningless w/o talking about the bullet and terminal performance. Wound cavity and specifically the design of the bullet in terms of terminal ballistics has more to do with its potential to kill. For example a little 62gr TSX bullet with solid design moving a very fast speeds is a devastating round given its consistent terminal performance. Equally a slow moving 308 heavy round that can reliably expand at moderate velocities can create huge trauma.
The best thing is to define the purpose, find the bullets one needs to use and then find a good case and system for that purpose and terminal performance.
One fact of physics is that the same bullet design with higher speed can reach further and one will see flatter trajectories and the same results at longer distances. Now the question is, is all that extra energy really necessary? At the cost of what? you decide. The AR platform is always about trade offs.
The 300BLK is here to stay. It covers two roles very well, specially its amazing subsonic capabilities and easy of use.
 
I'm currently in the market for a "larger than 5.56" Ar upper for hog and deer hunting use. I would say I'm probably fairly representative of this market in that I:

1. Don't own or plan to use a .30 cal suppressor
2. Don't plan on hunting with an SBR
3. Don't need a full up 30 rd magazine to handle Bambi or Wilbur

I guess I just don't see how the 300 BLK offers me anything over the 6.8 SPC II, 6.5 Grendel, or the aforementioned 6.5 BR. All of these rounds have superior velocities, SD's and BC's at similar bullet weights (110gr to 130gr) when compared to the .300. There is also no shortage of hunting type bullet choices in this weight range for the .277 and .264 cals. As for the .300 BLK being able to use standard 5.56 magazines, while neat, I don't really see this as a selling point, If I can buy a whole new upper or rifle, surely I can pony up for some new mags. The same goes for the bolt, If I'm getting another upper or rifle, I'm going to pickup a dedicated bolt or BCG anyway, and its not hard to find 6.8 SPC bolts.

In summary, while I think that the .300 BLK is an interesting round, I'm afraid that its strengths cater more toward the niche "Suppressors and SBRs" crowd than the "I want to hunt with an AR" crowd, which is certainly fine except that I would venture that the latter is far larger than the former. So while I imagine that the AAC will stick around for a while, I do not think it will ever be as popular or widespread as the 5.56 or even the 6.8 SPC.
 
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Scotty, in principle I agree with you completely. In reality, having sold rifles for a living, your average Bubba the deer & pig hunter doesn't get 6.5mm and 6.8mm calibers. Bubba doesn't get .260 Remington either. Bubba thinks 7.62 NATO (7.62x51) is "that AK round" (7.62x39). When Bubba asks for "35s" you have to ask him if he has a lever gun or a bolt action. If you ask .35 Remington or .35 Whelen, he'll tell you "Naw, it's a .35 Marlin"; which translates to: Bubba has a Marlin lever action chambered in .35 Remington. If he replies "Remingtons I guess, it's a Remington 700 in .35" that translates to: Bubba has a Remington 700 chambered in .35 Whelen. If he replies "I dunno, it's a Winchester rifle", your life just got interesting for the next few minutes. If you renamed the 6.8 SPC II the .270 AR-15, Bubba would get that. When you tell Bubba this .300 Blackout shoots just like a .30-30 but out of his AR-15, uses the same "clips" as his current .223, and he only has to drop this new top end on, Bubba gets that. I know that isn't / wasn't AAC's intent with the cartridge, but it's a nice alternate market.
 
Ha ha, you must live somewhere near me, I believe I may have met your buddy Bubba a time or two. Fair enough, I can see how that mechanism would channel folks towards the .300.

Bubba thinks 7.62 NATO (7.62x51) is "that AK round" (7.62x39).

hilarious... If I had a dime for each time I had heard someone say something to that effect... :rolleyes:
 
ugaarguy,
Bubba might be able to teach us one thing or two. LOL!

300 Blackout shoots just like a .30-30

I understand the enthusiasm. I like the blackout a lot specially due to the suppressed capabilities but one thing to like the blackout or the AK47 round, the other thing is to through comparisons like above that are not true. I hear all the time, the 7.62x39, the blackout and some others shoot like the benerable 30-30 but that is totally incorrect and people do not even bother to look it up. The 30-30 can send a 150gr bullet at 2400-2500 w/o signs of high pressure. The blackout and russian round simply do not have the case capacity to be able do that.

Here some 160gr loads...

http://www.hornady.com/store/30-30-Win-160-gr-FTX-LEVERevolution/

Anyone shooting and reloading the 30-30 can also confirm this....

http://data.hodgdon.com/cartridge_load.asp



Gtscotty,
If you like to reuse the brass but do not care about suppressed look at the 6x45. Like the blackout enjoys the use of many time discarded x1 fired cases, it is legal to hunt where for an inexplicable reason the 5.56 is not and the case prep. is super easy, many times even easier than reloading the 5.56.
Can shoot 85,87 and 90gr 6mm bullets for all sort of hunting applications.
Great on white tail, hogs and black bear. Very accurate.
 
Gtscotty, I won't try to convence you to use .300 AAC Blackout, since your mind is already made up.

To everyone else:

A 125 gr. Nosler Ballistic Tip will leave a 16" barrel at 2,200 FPS in .300 AAC Blackout.

That particular bullet will expand above 1,800 FPS, so you have a range over 150 yards. You can get close to 200 yards under ideal conditions.

At 150 yards that bullet will deliver 956 ft. lbs. of energy and 33.14 ft. lbs. per second of momentum.

For most hunters, a lightweight 16" barrel AR with this performance is a great hunting platform!

Let's be honest here. Very, very few hunters will make a shot past 150 yards or so. There is NO difference between 6.8mm SPC, 6.5mm Grendel, and .300 AAC Blackout to the majority of hunters out there.

Furthermore, if you want to shoot a deer or other similar sized game past 200 yards, you'd be pretty irresponsible to use an AR-15. If you do, you had better make sure you have excellent shot placement because no cartridge in an AR-15 delivers "humane" terminal ballistics at medium to long range.

An AR-10 with .243 Winchester, .260 Remington, or .308 Winchester delivers higher energy and momentum at medium to long range and you're more likely to insure a humane kill.

Of course, good shot placement is necessary regardless of the cartridge.

...the AAC will stick around for a while, I do not think it will ever be as popular or widespread as the 5.56 or even the 6.8 SPC.

What makes you think that?

What's easier for a manufacturer to support?

A cartridge that needs only a barrel change or a cartridge that needs a new barrel, new magazine, and new bolt?

When you're shipping 100 to 1,000 rifles per month, if the barrel is the only difference between two product lines, the choice is easy.

.300 Blackout is the easiest cartridge to support next to 5.56mm NATO. That fact will automatically make it the "winner".
 
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Gtscotty, I won't try to convence you to use .300 AAC Blackout, since your mind is already made up.

Whoa now, don't let me hurt your feelings, this is an opinion soliciting thread, and that's all I offered, an opinion. Besides, I wouldn't say my mind is already made up, its not like I posted:

" 300 BLK SUX, 6.8/6.5 RULZ!!!!!"

nope, instead it was more along the lines of:

I guess I just don't see how the 300 BLK offers me anything over the 6.8 SPC II, 6.5 Grendel, or the aforementioned 6.5 BR.

Relatively balanced if you ask me ( I know, you didn't.)

For most hunters, a lightweight 16" barrel AR with this performance is a great hunting platform!

I'm not saying that the .300 BLK won't work for hunting, I was merely posing the question of why I (and others of my ilk) should choose the 300 BLK when there are other existing AR rounds that, leave the barrel faster, hold on to their velocity better, and offer better penetration on the target (given equal bullet construction and weight). Again, I'm not saying the 300 BLK is a bad round, but just because it can be used to hunt doesn't mean there aren't better existing rounds for that purpose. Because of this, I still think it will likely be relegated to a niche status, but then again I've been wrong before.

What makes you think that?

What's easier for a manufacturer to support?

A cartridge that needs only a barrel change or a cartridge that needs a new barrel, new magazine, and new bolt?

When you're shipping 100 to 1,000 rifles per month, if the barrel is the only difference between two product lines, the choice is easy.

This seems to me to be a somewhat flawed thought process, you cannot generate demand simply by making something easy to produce and therefor plentiful. In other words, making something available in every shop, and on every corner won't necessarily make it sell... people still have to see a use for it, and want it enough to shell out the necessary clams. Even with all of the modern marketing techniques employed to sell widgets these days, there are still two sides to the supply/demand equation... supply and demand.

Jacked from Wikipedia:
" In economics, demand is the desire to own anything, the ability to pay for it, and the willingness to pay"

You'll notice there was nothing in there about how easy it is for the manufacturer to make or support a product. Point being, in the case of the 300 BLK, they've got the supply side ready to rock, but the long term demand trend for this cartridge has yet to be defined (it has only been a year after all).

.300 Blackout is the easiest cartridge to support next to 5.56mm NATO. That fact will automatically make it the "winner".

No.. it won't, see above.

Any round that is popular enough (read profitable enough), will be supported by astute companies, and you can hang your hat on that.
 
Ha ha, you must live somewhere near me, I believe I may have met your buddy Bubba a time or two.
Fellow North Georgian here. We've probably met a few of the same Bubbas. :D
ugaarguy,
Bubba might be able to teach us one thing or two. LOL!
Some of my best friends are Bubbas. They aren't ballistics nerds like me, but they're great shots, and always seem to have their freezers full of venison. Bubba is good people.
The blackout and russian round simply do not have the case capacity to be able do that.
I'm guilty of oversimplifying things. .30-30 Win is just the closest comparison. I've blown a few folks minds showing them load data & velocities on 7-30 Waters. It may not be high pressure, but that big ole .30-30 case necked down can sling 7mm bullets mighty fast. ;)
 
I'm not saying that the .300 BLK won't work for hunting, I was merely posing the question of why I (and others of my ilk) should choose the 300 BLK when there are other existing AR rounds that, leave the barrel faster, hold on to their velocity better, and offer better penetration on the target (given equal bullet construction and weight). Again, I'm not saying the 300 BLK is a bad round, but just because it can be used to hunt doesn't mean there aren't better existing rounds for that purpose. Because of this, I still think it will likely be relegated to a niche status, but then again I've been wrong before.

By what data are you using that demonstrates better penetration or expansion?

I would be surprised to see a ballistic gelatin test with a 6.8mm SPC bullet penetrating or expanding more than .300 Blackout bullet of equal weight and construction. The two aren't that far apart ballistically.

And by "niche status" is it any more of niche than any other AR round, including the 5.56x45mm NATO?

All cartridges that fit in an AR-15 are intermediate cartridges that don't do anything particularly well. They're all a compromise compared to full power rifle cartridges. At the expense of terminal performance, you gain softer recoil and the ability to carry more ammo compared to a full power rifle cartridge.

A certain percentage of AR-15 buyers want a cartridge with better terminal performance than 5.56x45mm NATO. Of that percentage, some will step up to the AR-10. The rest will look at 6.8mm SPC, .300 Blackout, etc.

From what I can see, the .300 Blackout is a more versatile round. It can perform as well, practically speaking, as 6.8mm SPC supersonic. It can also perform very well subsonic which the 6.8mm SPC cannot do well. It can also work in a standard AR magazine and bolt which the 6.8mm SPC obviously doesn't do either.

It's not flawed logic to say if more manufacturers support one cartridge over another, that more people will buy the more well supported cartridge. This is especially true given how close terminal performance is between 6.8mm SPC and .300 Blackout. A manufacturer is more likely to support .300 Blackout because it's easier and costs less to do so while doing everything the 6.8mm SPC can do.

Furthermore, AAC wants the .300 Blackout to be successful. Remington isn't pushing or marketing the 6.8mm SPC to the same extent AAC is marketing .300 Blackout. No other large company is championing 6.8mm SPC. .300 Blackout will likely win out as the most popular for marketing alone.

In summary, while the 6.8mm SPC got here first, there isn't anything it does that the .300 Blackout can't do just as well. The .300 Blackout is more versatile and can do things the 6.8mm SPC can't do well.
 
From what I can see, the .300 Blackout is a more versatile round. It can perform as well, practically speaking, as 6.8mm SPC supersonic. It can also perform very well subsonic which the 6.8mm SPC cannot do well. It can also work in a standard AR magazine and bolt which the 6.8mm SPC obviously doesn't do either.

Definitely more versatile. I disagree on "perform as well", as after obsessing with a ballistic calculator it is clear to me that good loads in the 6.8 SPC offer more power, range, and a flatter trajectory than any existing 300BLK loads (including handloads based on reliable manufacturer's data). The 6.8 has more case capacity and a smaller bullet - no real magic to having higher performance.

HOWEVER, I nonetheless chose to buy into 300BLK and forget 6.8 SPC, for three main reasons:
-none of the shooting that I personally do would benefit from the higher performance of the 6.8 SPC
-I have spare bolts and mags for 5.56, which work unmodified with 300BLK, but are useless for 6.8 (and 6.8 mags are expensive and difficult to find).
-300BLK is already significantly less costly than 6.8 SPC ammo and also seems to already have a wider base of ammo manufacturers. I don't like spending tons on ammo and I often don't have time to handload, so the price of factory ammo is a big deal to me.

In summary, while the 6.8mm SPC got here first, there isn't anything it does that the .300 Blackout can't do just as well. The .300 Blackout is more versatile and can do things the 6.8mm SPC can't do well.

Again, I agree on the versatile, I disagree on the "anything". If you want to hunt deer at 300 yards, 6.8 SPC is probably viable and 300BLK probably isn't. 6.8 SPC could also be used on paper to greater distance than 300BLK could, but if I'm shooting paper at long distance I'll be running either a .308 or a 5.56 with 77gr SMKs.
 
I'm not arguing that the 6.8mm SPC does not offer faster velocity and higher ballistic coefficient than .300 Blackout; however, I contend that it's not enough of an advantage to matter given the practical distance an intermediate cartridge is used at.

In other words, inside 300 yards, does it really matter?

Past 300 yards, you really should be using a better rifle platform altogether.

The 6.5mm Creedmore, 260 Remington, 243 Winchester, .308 Winchester, etc. kick the pants off any cartridge we're discussing in this thread.

The AR-10 isn't that much larger than an AR-15. For prone or supported fire, the AR-10 really shines as the superior platform for long range.

Where the 6.8mm SPC design is screwed up is it's focused too much on long range terminal performance. You don't need long range terminal performance in an intermediate cartridge. Trying to push the AR-15 to long range does have advantages, but when you can just put the AR-15 down and pick up an AR-10, those advantages only go so far.

What you need for the AR-15 is a cartridge that can perform extremely well inside 300 yards. You need an intermediate cartridge.

The .300 Blackout does that and gives you the option of running heavy 220 gr. bullets subsonic for use in a suppressor.

That versatility makes it the "winner". It fits the purpose and definition of an intermediate round better than 6.8mm SPC and far better than 6.5mm Grendel. It's easy for manufacturers to support because it uses already existing AR-15 bolts and magazines, so its adoption is a no brainer.
 
I guess it is possible I have not found it in a search... is there a thread out there anywhere discussing the specific performance tradoffs between the various barrel lengths; specifically between the 9" and 12.5"? Why did AAC bother to make these two lengths, this close together?

(9.0 + 16.0) / 2 = 12.5

It is exactly in the middle.
 
I don't know what you guys have been shooting with a 5.56x45 that you think it doesn't have terminal performance. Sounds like you all just shoot paper to me. In that case a .308 makes a bigger hole. You are correct about that.
 
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Gtscotty said:
I guess I just don't see how the 300 BLK offers me anything over the 6.8 SPC II, 6.5 Grendel, or the aforementioned 6.5 BR.

Just because 300 BLK works well with suppressors does not mean that it needs one. Just because it is efficient from short barrels does not mean that it does not benefit from longer barrels.

If you don't care about 30 round capacity, then how about 40% lower ammo prices than 6.8?
 
If you renamed the 6.8 SPC II the .270 AR-15, Bubba would get that. When you tell Bubba this .300 Blackout shoots just like a .30-30 but out of his AR-15, uses the same "clips" as his current .223, and he only has to drop this new top end on, Bubba gets that. I know that isn't / wasn't AAC's intent with the cartridge, but it's a nice alternate market.

Exactly.
 
My plan is to use 300 BLK for most ranges (99.9% of my shooting is within 200 yards), and a 308 for when I want more range - and skip everything else.

As for 30-30 comparisons - just be aware that 30-30 is reported I think for 24 inch barrels, and 300 BLK for 16 inch barrels.

The reality is - whatever velocity a 30-30 pushes a 150 grain bullet, 300 BLK will do that with a 125 grain bullet - in the same barrel length.
 
I can shoot a 125 grain bullet out of my 20" 30-30 close to 2600 fps, and if I really wanted I could probably reach 2600 fps safely. Can a 300 BLK/OUT reach 2600 fps from a 20" barrel?
 
I have shot 300 BLK at 2600 fps from a 20 inch barrel with 110 grain bullets, but I don't think it was within the normal 55,000 psi pressure limit.

In any case, I believe in only using SAAMI factory loads for comparison of ammo types, because they are controlled to a known pressure.
 
QuickLoad thinks 2500 fps would be at the SAAMI limit for a 125 grain in a 20 inch barrel.
 
The .300 is another intermediate AR cartridge, and thus a compromise. It is spin to claim that (unless you are selling it to the .gov/.mil) that using 5.56 mags and bolts is a benefit. It can also be considered a limiting factor.

First, decide that 5.56 is inadequate. Amazingly, it already uses commonly available magazines, a 5.56 bolt, and has cheap, available ammo.

Second, set your level of compromise (external ballistics, terminal ballistics, capacity, compatibility, etc).
-If you want to design a more powerful cartridge where the limiting factor is the receiver, you design something like a 6.8 SPC, 6.5 Grendel, etc. with an appropriate bolt and mags. A quick skim through Midway says that mags and ammo are reasonable, better elsewhere.

-If you want to design a more powerful cartridge where the limiting factor is the mags and bolt within the receiver, you get the .300.

If you could have only one, it becomes a personal choice. But hell, why only have one? :neener: It seems petty to me, but some shooters just NEED to have a .30 caliber bullet. Fine, go for it. If I go out for a hunt with some guys and someone has any of the debated "best" cartridges, I am not going to turn up my nose and we should have a good time.
 
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