Heavy 5.56 vs Mid 6.8 vs Light 308 for Defense

AR/M4 Beyond 5.56/.223
1

What caliber would be the best all around defense round of the three? I am thinking about close range (10-200 yards) with a 16" barrel. Just so I can get an equal comparison. I know this is highly up for debate, but I have been pondering the options. I’ve been considering at times dumping my 5.56s and going the 6.8 route, but I hear due to lack of ammo availability that, unless you roll your own 6.8, it is quite expensive to shoot, more so than .308. I, personally, like the whole concept behind the 6.8 and it seemes that price is the only limiting factor.

Through a defense perspective at 100 yards, which would give you the best ballistic ratings for your money. I have some very hot Hornady 75gr BTHP that I feel would make a good defense round due to the fact it is an expanding hollow point round that has a lot of energy due to the heavier bullet travelling at a velocity of 2600fps. I’m not sure how a mid-weight 6.8 round would compare to that of heavy 5.56.

I think some of the factors to consider are recoil, follow-up shots , penetration and expansion. How would the 6.8 round out of a 16" barrel compare with that a heavy and hot 5.56 round like 75gr Hornady, for example?

I am thinking that the .308 would obviously have the best ballistics of any of these rounds, but of course, the .308 is a bulkier round with more recoil. I am thinking, especially in CQB situaiton it would be hard to have accurate follow-up shots, although I know .308 would be better for longer ranges. Now, I am use to shooting 150gr NATO ammo and such. Does anyone know if there is any lighter .308 loads that are available and what opinions do people have about them?

2

You are asking for something all over the board. Before one gets into debate, define exactly what you need.

Define defense. Defense is NOT CQB and is rarely out to 200 yards (unless of course you are surrounded by marauding natives or Talibanis).

What or who are you defending from? 5.56 is not going to cut it against grizzly bears, and 5.56 will be more than adequate against rabid dogs, skunks, possums, racoons, and badgers.

You are also asking for what is best against your criteria for expense.

3

Sorry, I don’t know how to word it exactly. I am just looking for an all around good SHTF/zombie/ world coming to an end gun. You know, a one-size fits all? No, I don’t plan on using it for grizzly bears. I have 44 mag and 460 S&W for that application, but also would probably want to look into a higher cal hunting rifle or use my 12ga with slugs for grizzly defense.

Anyway, I am mostly going to be plinking from 10-200, maybe 300 yards. So, I would think any of the calibers would allow for decent grouping at those distances, assuming I do my job.

However, I would like to train with the caliber that I plan on using in a life/death scenario. It is really difficult to say, what one application I would use the caliber for. In reality, I don’t think anyone can predict exactly what type of situation they plan on using the rifle. So, I am looking for an “all-around” defense round for a variety of situations.

This is my go-to gun, when nothing else is avail. I hope you are following me?

Ok, let’s just say if I was stuck with one caliber and I had two guns. One being a SBR, like 11" CQB -style rifle and another being one for longer range, maybe 16" or 18" barrel on an A4 type platform, etc.

My goal is to train heavily with a caliber I want to shoot. Even, I am hoping to get into reloading for that caliber. I was thinking that dealing with multiple calibers is a hassle. Also, I feel 5.56, despite it’s glory, may have limitations. However, I have been doing a bit of research on these heavier 5.56 rounds and I am wondering how they compare in any variety of applications compared t a mid-weight 6.8 round. FOr example, hitting man size targets at 100 yards. But, then I wonder about how they would perform in situation where you are clearing a house.

All this is hypothetical , I’m just trying to look at the advantages/disadvantages of each of these calibers for variety of situations. Basically, I’m contemplating between 5.56 and 6.8 round. However, out of curiosity I would like to hear people’s opinions about light .308 loads and how they may compare in similar applications that I described.

My opinion as of now, is the 6.8 is all around a better round to use in all situations (except long range 600+ shooting), but the cost is prohibitive. But I could be wrong and that is why I am wanting to hear the wisdom from others.

4

For what you describe you should forget 6.8 as it would be much more difficult to scrounge ammo if needed (and proprietary bolts and mags would be unwanted). I would lean toward 12" SBR in 5.56.

5

Agree with previous poster, stick with 5.56. Responding to your question that I quoted above, the factors you listed to consider, and the calibers you mentioned: 5.56 makes most sense, get a good load for defensive use, such as the Hornady TAP 75gr loading, or the Mk 262 77gr loading. For better penetration, DocGKR (see Terminal Ballistics section and recommended 5.56 duty loads thread), is recommending a new 50gr Barnes TSX loaded by Black Hills. Another good defensive load is the Speer Gold Dot 64gr soft point, G&R Tactical has it available here.

Plenty of good 5.56 loadings to choose from, it’s the best choice for the conditions you describe.

6

5.56…

7

What exactly do you mean by “train heavily”? Forgive me, but the perceived context of your post is that you really have no idea what constitutes realistic training or expectations for defensive carbine use. It sounds like typical SHTF/zombie/teotwawki fantasy, reinforced by “plinking” at the range in a casual setting and thinking you’re good to go.

I’m not trying to bag on you here, but some time spent perusing this forum will reveal that most of the folks on here are gearing and training for actual serious use. Not just mil/LE, but civilians as well. That means careful selection of not just rifle and caliber, but all the ancillary equipment as well. It means taking training from respected trainers and then using those “tools” on the range until their ingrained.

Your best bet in this scenario is a good basic carbine in 5.56, several cases of decent quality but inexpensive ammo, and a basic carbine class from one of the recommended training groups. If there are any serious practitioners in your area, get with them and be a sponge. Understand that while it’s nice to be able to make shots out to 300 with your carbine, as a civilian your bread and butter is inside 50 yards. Spend most of your time doing drills for fast splits and transitions, to critical hits on small targets at ranges from 7 to 50 yds and back. Conquering mechanical offset is more important than doping wind at 300.

Once you have all that, you can get a 6.8 upper later. Getting one now is applying a hardware solution to a software problem. Let me reemphasize that I’m not bagging on you, but M4C is not TOS. Good luck! :slight_smile:

8

5.56 for defense against two legged predators, 6.8 and .308 for hunting four legged predators (although I don’t hunt :smile:).

9

Although 5.56 is not ideal, for the cost of converting to another caliber like 6.8 and its ammo costs, you can easily buy plenty of 5.56 self defense ammo and practice ammo. Read Dr. Roberts threads in the terminal ballistics section of the forum and pick up some of the recommended ammo, either non-barrier or barrier blind depending on your needs.

The .300 BLK cartridge looks interesting in the supersonic loads (125 gr .308" bullets) which perform like 7.62x39 in external ballistics, and have the added benefit of using same mags as 5.56 and same bullet selection as .308. Supposedly there is going to be fairly cheap ammo for it as well, not as cheap as 5.56 but much cheaper than 6.8. I do not know much about it but it looks like a possibility.

Personally, I don’t see enough benefit to convert from 5.56 for the added costs, but I might try one of those just out of curiosity. If cost was not an issue then 6.8 might be the ideal all-around cartridge for the AR15 platform.

I think for the military, cartridges other than 5.56 makes more sense for certain situations, because they are likely to engage targets out past 200 yds, or need suppression, etc. But the military also faces the issue of cost to convert and for most of the troops they are staying with 5.56.

10

Evergreen–You have been given some good advice.

I’d recommend before you do anything else, including purchasing a weapon, that you take the time to garner some additional knowledge and invest in sound training.

Read the following:

https://www.m4carbine.net/showthread.php?t=34714

https://www.m4carbine.net/showthread.php?t=44869

https://www.m4carbine.net/showthread.php?t=19881

https://www.m4carbine.net/showthread.php?t=19878

Then schedule some quality training–this is the most important thing you can do; officers in our area have reported outstanding training from Pat Mcnamara/TMAC, Magpul Dynamics, Trident Concepts, EAG, PistolTraining.com, VTAC, CSAT, Vickers Tactical, Fulcrum Concepts, ITTS, Kyle Defoor, and TigerSwan––you would be ahead of the game to get training from any of them. Some other folks offering good training include: Pat Goodale/PFT, Louis Awerbuck/Yavpai Shooting Academy, LMS Defense, Jason Falla/Redback One, Mike Pannone/CTT Solutions, Jim Smith/Spartan Tactical, Dave Hall, Don Lazzarini, and Rob Haught on shotguns. A lot of these classes are available through Grey Group Training.

Finally, for what you specify, a good quality 16" barrel 5.56 mm carbine with an Aimpoint RDS and simple SF 6v light would be your best option–Colt, BCM, DD, LaRue, Noveske, LMT, etc… If you want to go hunting, you can add an identically configured 6.8 mm upper later.

11

Which ONE tool is best all around for building a house?

Which ONE tool is best for fixing a car?

None, the job you are doing requires a specific tool.

Does your toolbox have one tool? No.
Why do that with your rifle.

There are pros and cons to all of them.

12

Choosing the “right” caliber will not save your life. The choice of 5.56, 6.8 or 308 will not change the outcome of a confrontation with a bad guy in your domicile. What will affect the outcome is mindset, tactics and preparation including training.

The 5.56 is less expensive than the 6.8 or 308 so you can shoot more to get to know your rifle.

Rifles chambered for the 5.56 are more compact and generally lighter than rifles chambered in 308. The 5.56 is also better suited to shorter barrels. The 300 BLK or 7.62x39 is a better choice for a 30 caliber carbine. From a 16" barrel their ballistics almost match the 308 from the same and do so with less recoil and muzzle blast.

Cost, compact size, good terminal performance, lower recoil and muzzle blast make the 5.56 the most practical choice for use in a defensive carbine for the civilian

13

Good post that I wish I had written. I still hold to what I posted, that 5.56 is the best choice for your situation as you described it, but as Mist says, there’s more to it than caliber choice. It’s easy to get too fixated on caliber at the expense of far more important questions that are more likely to impact the outcome of, say, a violent home invasion.

14

Thanks for all these valuable posts… I can already tell M4Carbine members have a lot of valuable info. I’ve been more of a pistol shooter for a while and have not shot my rifle much in years. I just sold my Rock River and currently own an LMT MRP CQB 16 and a DPMS LR-308. However, I am selling my DPMS LR-308, because I do not have the money to shoot the 308 round anymore. Particularly, my LR-308 is chambered tightly and is more of a match gun. If I get another 308 it would be one that can shoot the cheaper NATO ammo, which my LR-308 struggles with.

I think from what most people here have said, that I am best to work more on skills and tactics and worry less about stopping power. I do know well placed rounds generally are the most effective of all :D.

I understand that there is a different rifle for each application. I obviously I wouldn’t want an SBR 11.5 5.56 for Carlos Hathcock shots at 1000 yards. On the same note, I am a civilian, don’t have the money for expensive training programs and don’t have the government supplying me ammo. Nor, am I involved with firearm manufacturing. Not being a reloader, I got to pay top dollar for all my ammo. I’m hoping that will change soon. Also, I have hit quite a bit of financial difficulty as of late, so I am selling a lot of my guns and need the cash.

With all that being said, I think many people here have convinced me to stick with 5.56 and maybe work my way up once my skills improved. I guess I was wondering if there was any way to reload 6.8 to make it as affordable as 5.56, but I am doubting it, as I hear components are more limited.

However, I am interested in learning more about the 300 blackout round. I’ve a friend in Oklahoma who really enjoys shooting this out of his ARs. I’m thinking he is reloading it. If it is cheaper than .308 and comparable to 5.56, perhaps this would be a great round to invest in?

I’ve heard a few bad things about the 7.62 x39 round. Some articles I have read state that the round has some issues with aerodynamics of some sort. Something about the nature of how the round spins (or wobbles) results in worse accuracy. Please don’t quote me on this, but has anyone else heard anything about accuracy issues with the x39 round? I like to know. All I know is that my Saiga 308 is quite accurate at 200yds, whereas most people gripe and complain about their Saiga 7.62 x39s at the same distance.

I really appreciated the comment about the matching ballistics of the 300 BLK in shorter barrel compared to .308. Why waste the money and suffer the recoil when you don’t have to? It is like what I tell people who enjoy shooting .357s out of snubbies. I say, you are not gaining much velocity for all the torture you give your hands. But, it gives people the WOW effect, so they think they are cool. :stuck_out_tongue:

As of now, I am just wanting to learn my options. I’m thinking it is well to stick with 5.56 round, but I wouldn’t mine looking at alternatives.

As far as training, I just don’t have the money and resources. Most of these training courses seem to be catered for wealthy people or people sponsored by LE/Security or Gov’t agency who can pay the fees. I took an 8-hour Defensive Handgun I course at Oregon FIrearms Academy and it alone cost me about $600-800 if you consider all the ammo and money in gas I had to spend to get there and back. If there is any cost effective courses people are aware about where they teach you more tactics and techniques and spare you from dropping 1000s of rounds down the range, I may be interested in that.

15

I actually just purchased a 5.45x39 upper which I plan on running on an M-16 and SBR AR-15. The cost of ammunition will pay for the upper and encourage me to shoot more due to 10 cents a round ammo costs. For contact to 50 yard distances, accuracy is good enough for real training. I will also have some of the premium rounds and a 5.56 upper ready to roll after each range session. While high round counts will be with the 5.45 round, I’ll train with 5.56 too.

I’m shopping for an 8inch 300AAC Blackout upper for my SBR/M-16. Right now the ammo supply is a little low but, once the $12.99/20 ammo becomes widely available I will reconsider my 5.56 needs. The 300 AAC Blackout will have a lot less muzzle blast, especially in a house, then a 5.56 so that combined with the use of a suppressor offers great promise in the next year.

16

Evergreen–Rather than using money to purchase $500-1000 dollar handguns and rifles, you would truly be better off using those same funds to get GOOD quality training.

Most people would be FAR better off owning 2 identical 9 mm Glock or M&P handguns and a well built 16" 5.56 mm AR15 (Colt, BCM, DD, LaRue, LMT, Noveske, etc…) and spending the rest of their resources on training, rather than collecting a bunch of firearms that they will NEVER learn to master.

7.62x39 mm works fine in AK’s, just not in AR15’s. The .300 BLK give 7.62x39 mm external and terminal ballistics, but in a cartridge that works reliably in an AR15.

17

Component cost is more for a 6.8SPC so, reload to reload the 5.56 will still be cheaper.

This is essentially a 300Whisper taken through the SAMII spec process. For most people, a 300 AAC Blackout will make more sense then a 308 AR rifle. It works subsonic and suppressed AND supersonic. Supersonic ballistics are in the 7.62x39 and 30-30 range while still fitting in the smaller AR-15 form factor.

Bad ammo shoots badly. Good ammo shoots better. Some AK clones are really bad rifles so that can be a factor too. A quality rifle with quality ammunition is in the same league as any other battle rifle. Some are better in some instances then others but, the tables turn in other instances.

Bad ammunition in your AR-15 will shoot poorly too. Personally, I find the 7.62x39 to be a great choice for most situations worldwide. If the shot is 600+ yards at a man sized target, I’ll take an AR-15/M-16. Inside 300 yards I’ll take a good AK-47. Krinks are sweet in urban situations.

18

Hi DOc,
I was not planning on buying any more firearms. Although, I was considering trading some, perhaps. Actually, I have sold quite a few firearms because I need money. However, I am not sure if a 1 day course can compare with over a month of training at the range. Especially, if I am reading books or learning techniques/tactics from people online. I understand that nothing beats good training with a skilled instructor face to face, but my resources are limited. IMO, if you don’t frequently practice what you learned in courses, you can also forget. I felt I learned more from shooting with other people at the range who were experienced then I did at my OFA Defensive Handgun I course. As much as I liked the course, I felt it wasn’t worth the hundreds I put into it. If these courses were cheaper, I think they would be way more valuable for me. Sadly, I don’t have people to sponsor me or pay for my training.

As far as wasting money on more guns, you are preaching to the choir now. About 4 years ago I was stocking up on guns and now I regret it. Actually, I am trying to keep things very simple. That is why, I would like to have one caliber and just one or two guns of that caliber that I can train with. Basically, I would like one rifle for the close range and another rifle for longer range shooting.

FYI, I do have two S&W M&Ps , 1 .45 and 1 9mm… The handgun is affordable and works great for me; I’ve never needed another. I sold my Sig P229 to fund the purchase of my M&P 9. My 45 is safe queen, my 9 is my CCW. I have several revolvers, but each for different applications.

Basically, I am clearing my safe out of the tactical weapons and just want one or two I can trust and make the most use of. Hence, the reason for this post.

I was told that 7.62 x 39 has a tumbling issue that results in its poor accuracy out at farther distances. I’ve never heard it was any different in an AK or AR. Wasn’t really aware they had 7.62 x 39 ARs, although I am sure they exist.

I’m very happy with my LMT and don’t really need another brand. I was just thinking about caliber, but I am thinking that 5.56 would be most cost efficient and effective. I think I would prefer to plink with steel case 5.56 over 5.45 round. I’m not too familiar with it, but I would think 5.56 is as low as I would go. If I want to plink with anything lighter I would go for a 22LR conversion kit or a 10/22.

I guess I need to do some homework on the 300BLK round. Sounds promising. Although, with my current financial situaiton, I guess 5.56 would be the best, even if I start reloading. I am hoping to get a reloading setup going here soon. I have some nice reloading books, but not the equipment. Although I have saved for myself some 5.56 brass.

19

For plinking and personal defense, a 16" 5.56 mm AR15 is fine; heck for plinking a .22LR is even better. In your situation, you would only need a .300 BLK or the even more effective 6.8 mm if you plan on hunting with your AR15 and being able to harvest all game up to Elk size in the lower 48 states.

Quality 7.62x39mm ammunition shot from a good rifle works just as well and is just as accurate as any other caliber.

There is no substitute for taking a class with an experienced trainer. In addition, many individuals find they are actually saving money by taking a class, as you will be able to focus on effective drills when you are later practicing at the range on your own time, rather than just wasting rounds doing ballistic masturbation as so many folks seem to do when going to the range.

20

Doc, do you think there would be any meaningful knowledge I can gain from reading books and watching videos from skilled trainers? As much as I would like to do training, I don’t have the time or money right now. I work like 60-80 hours week right now. I’m lucky to get a day off at the range. However, I would love to attain as much knowledge as possible, until I can allot time and funds for a good training course. Also, I am always interested to find low-cost training courses that would be deemed effective.

I just don’t like the type of courses where they have you blow so much excessive amounts of ammo. I think these courses might be a bit outdated perhaps and were probably developed back when ammo was actually affordable. On another note, perhaps I can consider classes where 22LR would be acceptable in the course; obviously, not feasible for any long range rifle type courses.