308 for civilian use makes sense, since we aren't going to lug it around for days with 100's of rounds of ammo
if I did have to lug around for days with ammo, maybe 5.56 would be better
both calibers are readily available, which is important too

Things to consider:

1) The 223/556 is a very common round. Easier to find for sale and barter with than 308.  I've seen way more 223 on the shelves than 308.
2) LEO here is almost all 223/556 for rifle caliber
3) Military here is majority 223/556 for rifle calibers.
4) Penetration of each caliber, depending on what your home is built from.
5) Ability to rapid fire accurately
6) Urban distances
7) 223/556 is cheaper to practice with and so are the rifles that shoot it

In the end it's your call. But for me, I have no reason to buy a 308 semi auto.

Considering ditching my 5.56 carbines for a .308?  No. 

I do have and envision having bolt action in .308 and 6.5 CM for the foreseeable future, but not quite the considerations MAC noted. 

I like having both calibers 5.56 and 308
I wouldn't give up either one
for SHTF like red dawn and I'm staying at home, then I would prefer the AR308. way more stopping power. if I need to shoot through barriers, 308 is much better
but for SHTF and I need to bugout, then I would prefer the AR15. lighter rifle and lighter ammo to carry. if I have to bugout and I know I'm not coming back home, then I would take both rifles with me
if I need to hunt, 308 is better suited. 223 or 5.56 I don't think is legal to hunt here. I could be wrong bc I'm not a hunter. but if the need arises, I'd prefer 308 over 223
I shoot way more 223 than 308 mostly bc of cost. and I have twice as many 223 rifles than 308 rifles
I shot my AR308 on a friend's farm a few times, mostly offhand position standing and it got heavy real quick, it weighs almost twice as much as my AR15's. but that's just my rifle, others might weigh less.  plus add in a loaded 25 round mag and now its really heavy, so I wouldn't want to lug that around for too long
I don't think there is a do it all gun, each has a specific purpose.  I would hate to have to choose only 1

Keeping .556 because I’m a wimp.
Had a cheap 7.62x39 upper. Was reliable but I couldn’t get it accurate. Shoulda kept it. Was good fun.

If you're repelling a foreign invasion and happen across a fallen NATO soldier or supply point, chances are good you'll find some 5.56 ammo.

Of course, you can also get 7.62x39 off the enemy, but that involves more risk.

 

I think I'll keep my 5.56

Yeah, in the case of SHTF or civil chaos, there will be a lot of people running around shoot'in and pillag'in all over the place.

If I ever end up in a shooting match and I luck out and come out on top, chances are my enemy has a 5.56/.223 which I can add to my arsenal.

5.56/.223 will be a popular bartering item as well.

Since we live in Hawaii, most likely we will have a hurricane or tsunami vs a red dawn invasion
In that case, I will be hunkering down at home defending against looters. Probably 1 looter or a few at most at 1 time. That means I wont be lugging ithe AR308 around so its heavy weight isnt a factor. What is a factor is the 308 has about double the energy of 5.56. It will take less rounds to stop a threat.
5.56 will get the job done. 308 will get the job done better

Kinda off subject but on Hurricanes and Tsunamis:

If any one hits with deadly accuracy one can almost be assured there will be total chaos resulting in pillaging and looting.

We are isolated.  We cannot divert power from other states or sources.  Our supplies come from 3000 miles away over the water.  If our harbors and unloading docks are damaged........

But my biggest concern is our people.  We are untested as far as prevailing during times of duress.  I suspect the majority of the population panicking and doing irrational things.  Politicians will be hiding in their basements.  HPD will hunker down and take care of their own.  I don't blame them.

Yep.  Sometimes I long for a .308 and if the above days do come, I will wish I never procrastinated.

Kinda off subject but on Hurricanes and Tsunamis:

If any one hits with deadly accuracy one can almost be assured there will be total chaos resulting in pillaging and looting.

We are isolated.  We cannot divert power from other states or sources.  Our supplies come from 3000 miles away over the water.  If our harbors and unloading docks are damaged........

But my biggest concern is our people.  We are untested as far as prevailing during times of duress.  I suspect the majority of the population panicking and doing irrational things.  Politicians will be hiding in their basements.  HPD will hunker down and take care of their own.  I don't blame them.

Yep.  Sometimes I long for a .308 and if the above days do come, I will wish I never procrastinated.

We are the Aloha State. Lots of Aloha to go around.

But shot placement is the ultimate factor.

Kinda off subject but on Hurricanes and Tsunamis:

If any one hits with deadly accuracy one can almost be assured there will be total chaos resulting in pillaging and looting.

We are isolated.  We cannot divert power from other states or sources.  Our supplies come from 3000 miles away over the water.  If our harbors and unloading docks are damaged........

But my biggest concern is our people.  We are untested as far as prevailing during times of duress.  I suspect the majority of the population panicking and doing irrational things.  Politicians will be hiding in their basements.  HPD will hunker down and take care of their own.  I don't blame them.

Yep.  Sometimes I long for a .308 and if the above days do come, I will wish I never procrastinated.

I'm sure a 5.56 will do the job.  I'm just Mr. Overkill. 
Like ren said, shot placement is key.
But there's still time to get a 308 if that's what you want.
I like options. I never regret buying a firearm, but I did regret not buying a firearm

Kinda off subject but on Hurricanes and Tsunamis:

If any one hits with deadly accuracy one can almost be assured there will be total chaos resulting in pillaging and looting.

We are isolated.  We cannot divert power from other states or sources.  Our supplies come from 3000 miles away over the water.  If our harbors and unloading docks are damaged........

But my biggest concern is our people.  We are untested as far as prevailing during times of duress.  I suspect the majority of the population panicking and doing irrational things.  Politicians will be hiding in their basements.  HPD will hunker down and take care of their own.  I don't blame them.

Yep.  Sometimes I long for a .308 and if the above days do come, I will wish I never procrastinated.

With recent near-misses and increased homeless over the past few years, I think if one hits with even moderage impact, things will be at least amplified.  I think many have gotten lulled into a sense of "Lie Hagi wen lie again".  Hopefully some folks are better prepared overall based on recent stuff, like pandemic supply chain issues, realization that one can't depend on Gov't or others for help, etc.  That said, I agree that the biggest concern is people looking to "get theirs". 

Here I go again straying off topic.  (Sorry guys, it's an illness.)

Anyway remember a while back when Walmart used to have those bluelight specials or Black Friday specials and they put spam on sale? Forget what the price was but it was case sales and dirt cheap.

The video showed a huge braddah fighting off little ole ladies.  Just for a f*ckin case of spam.

I think of that scenario everytime a Hurricane approaches Hawaii.

5.56 is perfectly fine for self defense use for most people.  Ammo is half the cost compared to 308 to allow for more training.  The rifle, and ammo, is lighter so it'll be faster to get on target, move with the rifle, and do followup shots.  Muzzle blast will be less indoors.

Some of the complaints that 5.56 is weak can be attributed to using FMJ instead of JHP or JSP.  308 has a lot of power, but a lot of that is wasted when the bullet exits the body.

308 is good for penetrating barriers and keeping energy at long ranges, but those factors aren't as relevant for most people.

308 is good for penetrating barriers and keeping energy at long ranges, but those factors aren't as relevant for most people.

How do green tips compare to FMJ 308 for penetration?

Also common 308 mags come in 20rders like the Scar, M1/14, AR10.  Unless u go 7.62 AK versions. Compared to your common 556 mags that are 30rders.

308 green tips.   

I have no plans to get rid of any ammo/guns. I enjoy all of my 556, 762x39, 308, 6.5, and
545x39 platforms. You never know when an opportunity to acquire may present itself.
I can however appreciate the benefits of simplifying a firearms/ammo inventory.

5.56 is green tips, 308 is soft points 150 grains, 7.62x39 is 122 grain fmj
the 308 penetration would be more with a fmj projectile

I have no plans to get rid of any ammo/guns. I enjoy all of my 556, 762x39, 308, 6.5, and
545x39 platforms. You never know when an opportunity to acquire may present itself.
I can however appreciate the benefits of simplifying a firearms/ammo inventory.

Same/similar for me.  For SHTF or even all-around use, commercial ammo availability for 5.56 and 7.62x39 are quite common for "2 legged" considerations.  For .308 and 6.5 I mostly have match ammo and heads.  I have some hunting ammo for them, but damn expensive.  Now thinking about things a but more, my AK is seeming quite attractive for all-around use, at least where I live. 

How do green tips compare to FMJ 308 for penetration?

Also common 308 mags come in 20rders like the Scar, M1/14, AR10.  Unless u go 7.62 AK versions. Compared to your common 556 mags that are 30rders.

Overall 308 will vastly out penetrate m855 just cause it's got a lot more mass behind it and a thicker jacket.  There are some exceptions.  M855 will penetrate a slightly thicker steel plate.  Though a 308 AP round would go through the same like butter.

You give up stopping power for penetration by using m855 over JHP or JSP.

For peacetime purposes, a 20 round magazine is okay with aimed fire.  Capacity isn't as important as with pistols since a rifle is more accurate and require less hits to stop an attacker.  Unless the cartel is after you.