.30 cal FMJ rounds, what makes them better then 5.56 FMJ?

[The Alaskan]

How can anyone honestly not understand how one projectile with 3X the mass and 2X the energy of the other, is more effective

That's kind of what I was getting at, too.

Why does 2+2=4? No.....2+2=22.

 

[Art Eatman]

I've shot a bunch of GI 5.56, plinking. .223 soft points on coyotes and jackrabbits.

I've shot a bunch of '06 M2 GI ammo on trees and rocks. With soft points, I've killed a fair number of deer.

Okay. I figure that I have a handle on comparative performance.

The heavier bullet will penetrate more deeply at any distance.

If "effective" means a dead enemy from a center-mass hit (a head shot from a pipsqueak cartridge can easily be fatal), the heavier bullet will be effective at a longer distance.

 

[X-Rap]

So what is it that makes the 7.62 NATO and the venerable .30-06 such a superior combat cartridge in terms of lethality to the 5.56? Beyond the need to reach out and touch someone (often overstated) by what mechanism is the .30 FMJ bullet made superior t0 the 5.56?

I'm asking this in all seriousness due to often repeated mantra of .308 being a better caliber for social work. Now I'll certainly agree that once we get out of military FMJ rounds, that .30 caliber bullet selection is more lethal than a comparable loading in .223; however the question is regarding military FMJ rounds.

There is no question that the .30 is superior in weight and energy, Ray Charles could see that but given the solid composition of the bullets in each caliber I believe it certainly equalizes them to some degree.
The superior combat lethality of the .30 round is questionable IMO since the comparisons are skewed by the fact of factoring two WW's, Korea and part of Vietnam in which without question many men were killed but many ship loads of .30 ammo were expended.
Does anyone have a ratio of shot fired per kill in any of those conflicts?
How about the .22 performance ratio from Vietnam on.
Of course then you will have any statistic skewed by the use of .30 being used extensively in crew served machine guns rather than individual rifles in all those wars.
I guess in this case I'd have to ask for some proof of the original premise before I would agree that one is better than the other.

 

[Mosin Bubba]

How can anyone honestly not understand how one projectile with 3X the mass and 2X the energy of the other, is more effective.

The real question is how anyone can claim the projectile weighing a third as much, with half the energy, can be as effective as the bigger & harder hitting one. This is where the magic voodoo yawing/fragmenting/elastic/radioactive theories come into play.

Yeah, that's the question under debate, but I think the contrary of it is just as important to consider. The 308 obviously has a lot more juice than the 223, but can enough of that energy be turned into damage to justify the heavier rifles/ammo and much greater kick?

I'm definitely no expert on the subject, I'm just reading and learning here.

 

[Zerodefect]

If barriers and distance are involved, the .308 is worth it. But 500 yard or less engagements, I'll take the lightweight, easier to move with 5.56. And the new 5.56 rounds do very well. In my local terrain, .308 just isn't needed.

A 6.5 Creedmore AR10 sure would be nice though. Obviously, most are setting up their ar10's for long rang with scopes, and AR15's for shorter ranges. Not many .308's with red dots out there. But there's nothing wrong with setting up ann Ar10 as a carbine, and a Ar15 as a rifle. Special choices, for special missions.

 

[Vern Humphrey]

If barriers and distance are involved, the .308 is worth it.

It has been my experience there are always barriers involved. People tend to get behind things when the shooting starts.

 

[Swampman]

Originally posted by Jenrick
My question is WHY the "common fighting man" felt so strongly about transitioning to the .223. The whole "poodle shooter" "varmint" cartridge thing.

Regarding the "varmint cartridge thing", what else would you expect soldiers to think about being used as guinea pigs to test a .224" round in combat for the first time? 5.56x45 was first issued to regular combat troops in 1965 and at that time, a "varmint cartridge" was pretty much defined as anything in .22 caliber.

Lets look at a couple of the more popular .224 rounds that had preceeded .223/5.56, the .222 Remington and the .220 Swift. The .222 is slower than 5.56x45 and the .220 is a good bit faster and more powerful.

Both of those cartridges were designed, intended, loaded and marketed as VARMINT cartridges.
The bullets they used were very lightly constructed and designed to fragment instantly on contact.

Hunters that tried the high velocity .22's on large game generally had poor results, mostly because the bullets weren't designed for hunting, they blew up too fast and didn't penetrate well enough for consistent killing power.

THAT'S why a lot of troops considered the 5.56x45 a varmint cartridge.

As for the "poodle shooter" moniker, that's because JEFF COOPER SAID SO!

 

[AStone]

I need to get caught up reading in this thread.

 

[Vern Humphrey]

THAT'S why a lot of troops considered the 5.56x45 a varmint cartridge.

The troops considered the 5.56X45 an INADEQUATE cartridge, and the M16 rifle as issued in the 1960s was frankly not ready for prime time.

Modern ammo and M16/4 rifles are a long way from the crap we had in Viet Nam.

 

[Swampman]

@ Vern
The OP asked specifically why troops would have considered the .223 to be a "varmint" cartridge back when it was introduced as standard issue and I attempted to explain the reasons behind that.

Many of today's shooters don't understand just how limited bullet selection was for the .224 bores until fairly recently. Pretty much all the civilian projectiles available were designed for varmint shooting until the introduction of the Speer 70 grain, semi pointed flat base in the (IIRC) early to mid 1980's, 20 years after the introduction of the M-16.

In any case, I think it's fairly clear that troops referring to their newly issued weapons as "varmint guns," "poodle shooters" or "Mickey Mattels" probably weren't doing so to express their boundless confidence in the new plastic rifles and associated small caliber ammunition.

Inadequacy and a general lack of faith seem pretty strongly implied by those terms.

 

[tactikel]

.30 cal FMJ (and 8mm, etc.) are proven over a Century to be effective in combat.
6.5 mm to 8mm FMJ military ammo have claimed uncounted millions of lives since 1898.
Technology, increased rate of fire, the need for greater mobility, lighter weight anno, and the circumvention of the "Geneva Convention" protocol in projectile design spurred the trend to 5.56 mm adoption.
the .30 cal has over 2.5 times the surface area, 2.7 times the mass, and 1.7 times the ME of the 5.56 Nato. This is significant.
My AR will put 30 rounds down range about the same time as my 1903A3 will put 5 rounds. This is significant.

 

[Vern Humphrey]

In any case, I think it's fairly clear that troops referring to their newly issued weapons as "varmint guns," "poodle shooters" or "Mickey Mattels" probably weren't doing so to express their boundless confidence in the new plastic rifles and associated small caliber ammunition.

It wasn't just the ammunition -- the weapon itself was inadequate. Consider one simple point -- the original triangular forearm tapered FORWARD. And this was a rifle designed for full auto fire -- so recoil (which of course pushes backwards) made it difficult to control the weapon in full auto.

The AK 47 had a chrome-lined bore, the M16 didn't. The early magazines were unreliable and had to be downloaded to be sure they'd work. The early rifles were supposed to be "self cleaning" and were issued without cleaning gear. It was like a script written for the Three Stooges.

 

[d2wing]

I have used both weapons and ammunition in various forms both in combat and in hunting. My favorite weapon is the M-60. The Army has found that the lethality per round could is about the same in actual combat with a slight advantage to the 5.56. That is because of more hits and a higher percent of energy converted to wound damage at closer ranges. No one in his right mind would doubt the greater effectiveness of the 7.62 in a side by side comparison especially at ranges beyond 150 yards. However at closer range there is little difference.
However as mentioned use of barriers and body armor would give the 7.62 an advantage as would distance. We have not faced an enemy yet that uses armor, and while much shooting is behind barriers not enough of those shots are directly aimed at a person to make a known difference. Those of you like me that have been in actual combat know that volume of fire is basically what happens. Most of what is said on here has little bearing on actual combat. And most of what is posted is totally ignorant of actual wounding mechanisms. And the person that claims momentum rather than energy kills is a product of Internet quackery.
The ability of a bullet to destroy tissue is directly related to its velocity,,energy and deformation. Mass and size do count. A 7.62 can often exit a body before it deforms and just leave a hole as opposed to a wound cavity. The less stable weaker smaller bullet at higher velocity is more likely yaw and deform transferring more of it's energy quicker.
If you ever saw real wounds you would see that.
So While the 7.62 is more powerful and is more effective at longer range by a lot, and more effective against barriers, don't sell the 5.56 short. It has proven it's worth for 50 years now, in real combat. You just have to realize any cartridges limitations. I always bigger and faster is better, but you have to consider other factors from time to time.

 

[d2wing]

As I have said in the past, it depends on the situation. For defending a fixed position with a place to rest your rifle like sand bags against an approaching enemy especially at a distance I would pick the M14. A good friend of mine used a armory built M 14 with a Leupold scope to great effect as described in the books, Black Horse Rider, and Fire Base Illingworth. Two fierce battles in Veitnam that were documented in books by Historian Philip Keith. He was able to inflict heavy losses on NVA soldiers hidden in bunkers that others could not see in one instance. However he was targeted and nearly killed when the NVA caught on.
My weapon of choice in those type situations was a belt fed Machine gun firing the same bullets as the M14, 7.62 NATO.
However for laying down fire, especially in an typical ambush a lighter fast pointing with a high rate of low recoil fire is better. Not just my opinion, this has been proven over and over for the last fifty years. True the 7.62 NATO covers more bases. What is best for the Army may not be best in your situation. They have back up with heavier weapons.

 

[cdb1]

Because the .30 caliber bullet is larger. Period.

35W

Yep, .308 makes a bigger hole.

 

[Zerodefect]

It has been my experience there are always barriers involved. People tend to get behind things when the shooting starts.

Maybe, but you aren't going to flank around a barrier too quickly with an AR10. They're in the "heavy metal" class in 3 gun for a reason. Can't compete with AR15's and P90's if you need to move.