When To Choose A .308 Over 5.56?

[TehLlama]

How effective is the 223 M855A1 on a no body armor target at 600 meters vs the 7.62 x 51 M118LR?

At that particular range and those particular loads, that's an apples to watermelons comparison - smaller caliber semi-penetrating projectile against a 30 caliber reverse drawn open tip match projectile that deforms across an impressive range of velocities? In the cartridges in question one is already down to the sub- 1.5 Mach region where some bullets don't seem to want to deform or yaw, while the larger projectile is already traveling at a higher speed [almost exactly Mach1.5 @sea level ~625yd] and in a design that is more likely to either deform or yaw after encountering soft tissue.

Comparing more similar setups (Mk318 62gr 5.56x45 to Mk319 130gr 7.62x51) [Mk262Mod1 77gr to M118LR 175gr] would yield less divergent results.

At the rate this discussion is going, I'm really going to want to figure out what realistic soft target testing has been done with these projectiles in velocity equivalent analogs to longer range terminal effect - this information alone may sway me towards wanting to run a battle rifle (read 16" 7.62 gas gun) for basically everything between 400-800 meters unless I'm hunting exclusively paper and other inert targets).

[Markk9]

As a follow up post... In a SHTF situation what ammo are you most likely, to easily find? I would have to say 9mm, 40 s&w, .223, 308, and 22 rimfire in my local area. The most likely scenario for a large mass SHTF situation, in my opinion, is an EMP attack on the US or part of the US. Given that, I would plan to shelter in my home, with my AR-15 in 223 as my primary weapon. Next question, what ammo is National Guard going to be issued to deal with civilian control? What ammo are the local LEO's going to have? This is going to be the major ammo source for resupply. This situation is going to be different for everyone, it's really going to depend on the environment around you.

[MistWolf]

The only ammo, firearms and spares you're going to find when the "SHTF" is what you have on hand. There is something strange in picking a firearm based on what you're most likely going to be able to loot off the dead. Or do people think the apocalypse is going to be a video game where they just have to go to a spawning point to pick up gear?

[Markk9]

It's not going to be like a video game! I have about 2K of 223, about 3K of 9mm loaded on the shelf, have enough powder, primers, and bullets for another 5K of each. I have over 10K of 22 rimfire on the shelf. In a long term SHTF like my EMP theory, you are going to be "looting" food, water, and ammo at some point. I don't think the law enforcement and national guard will be able to keep the peace in a long term crises. I keep about 3 weeks of canned food, and bottled water for the family on hand at all times, for a short term crises.

[MorphCross]

The only ammo, firearms and spares you're going to find when the "SHTF" is what you have on hand. There is something strange in picking a firearm based on what you're most likely going to be able to loot off the dead. Or do people think the apocalypse is going to be a video game where they just have to go to a spawning point to pick up gear?

I blame Battlefield and Call of Duty for this viewpoint. National Guard and Local PD is not going to hand over their ammo to anyone. It would be naive to believe that the Military's Small arms ammunition manufacturing is hardened in any way against aerial assault or an EMP. It's remoteness is its biggest advantage against human pilots. An EMP detonated high in the atmosphere over the US using an ICBM system doesn't have to worry about that.

Once the military's small arms ammunition manufacturing grinds to a halt, the ammunition anyone has in America will be the extent of what they have to use.

[Markk9]

There is going to be a lot on commercial ammo that is in just plain old warehouses waiting to be shipped. I don't expect LEO and National Guard to hand over ammo, but after a long term SHTF, do you really expect there to still be order in society?

[bzdog]

The only ammo, firearms and spares you're going to find when the "SHTF" is what you have on hand.

xactly

[Symmetry]

For a SHTF situation, it is all a question of what the scenario will be. If I am holding up with my family in a single location, then .308 makes a nice choice for defending the castle and shooting game(if there is any left at that point). The .30 cal rounds do a better job of punching through a variety of cover, you have less range limitations, and if you score a hit that hit is more likely to incapacity quickly. In a mobile situation, where you must leave one area and move to the safety of another, carrying around a .308 platform and its ammo becomes a burden. You may be moving on foot due to choked roadways, and you are literally carrying everything you choose to own on your back. In that case, 5.56 all the way. So, if you are in a good rural area where you can likely hold up .308 is good, but if you are in any sort of urban interface I would prefer 5.56.

[Failure2Stop]

Keep it on topic and out of fantasy.
If your post is going to contain reference to a video game or movie, don't even bother posting it, because I'm going to trash it.
This thread was rolling merrily along with good discussion, don't shit all over it now.

[markm]

How effective is the 223 M855A1 on a no body armor target at 600 meters vs the 7.62 x 51 M118LR?

I'd love to get my hands on some of the projectiles out of M855a1. There've been posts here from guys who've seen its effects on torsos and heads and stuff. Supposed to be pretty good at tissue damage.