M16/AR-15 Clones

[Legbreaker]

I've shot both the 7.62N (L1A1 plus a few hunting type rifles) and the 7.62S (SKS and SKK). The 7.62N definitely has the greater recoil, however it's also a much more accurate round.
In my experience, the 7.62S is more of a "spray and pray" type round - provided you can handle the recoil. Forget about trying to hit anything accurately at more than a couple of hundred metres (I was a fine shot in my day and found it quite difficult compared to the 7.62N).

[StainlessSteelCynic]

Just a couple of things to say, the whole idea of the intermediate round was based around the recognition that most engagements occurred within 300m and typically within half that distance. It was therefore considered that a longer ranged round wasn't necessary for most infantry troops as they wouldn't be shooting past 300m most of the time.
In regards to the Soviet M43 7.62x39mm round being based off the German 7.92x33mm Kurz round, I'd agree that it was certainly influenced by the German round but the Russians had been developing intermediate rounds almost in parallel to the Germans for about the same length of time if not longer. They both had numerous ideas resulting in various cartridge calibres and lengths but to say that the M43 was based off the 7.92mmK is a bit misleading.

[HorseSoldier]

Originally Posted by Legbreaker

No, based on experience I strongly believe now and always that the M16 and it's variants is not the best possible and doesn't even come close. Nothing in 5.56N can possibly match the power and lethality of a 7.62x51 round. Accurate shooting by a skilled marksman might close the gap somewhat, but 5.56 will never be as devastating to a target.

The brass cased cartridge is a very mature technology ("stagnant" is another term) and so at this point everything is really just about deciding which set of strengths and weaknesses you want to accept. 7.62x51 undoubtedly hits harder, but at the cost of a smaller basic load of ammo (both reducing overall staying power in a fight as well as the number of potential engagements), a heavier overall weapon, and weight/recoil issues that make weapon handling speed slower than intermediate weapons.

5.56mm more or less doubles practical basic load, and is a much faster handling cartridge (all other things being equal), but it certainly gives up thump. I'm comfortable with what the round can do (and what it cannot do), but feel that the sweeter spot in terms of trade offs is more in the range first proposed by the British after WW2, with 7mm-ish and 110-130 grain kind of bullet weight. 6.8x43 Remington SPC just about reinvented the 280 British round that got shot down by US advocacy of 7.62x51 (which is really just "30-06 Short"), though with a somewhat lighter bullet at higher velocity due to the limitations imposed by the AR-15/STANAG magazine and mag well dimensions.

Of course, exactly where that sweet spot is in terms of modern training and technology is an open debate. Some of the advocates of 6.8 Rem SPC are now working without the limitation on case overall length and are proposing a 7x46mm round that looks even more like 280 British (130 grains at 810 meters versus the originals 139 grains and 770 m/s).

[Gorbag]

As was stated in an earlier post, shot placement with the 5.56 is essential. IMO, the round's lethality problems can all be traced to the "green tip" projectiles (the M855). The projectile itself is intended to punch holes in body armor at a distance, and this just leads to "ice picking" on those unfortunate enough to be hit (basically just poking little holes through). I saw Somalis get up and run away after taking a pretty sizable burst from a SAW, and others drop with one or two rounds that hit center of mass and popped a critical organ or blood vessel. The capabilities of the cartridge have been enhanced somewhat with the new Mk262 projectiles, but cost is keeping that stuff from general issue.

The cartridge at its basic form is plenty lethal. It's just not geared towards one-shot-stops of human sized organisms. But, truth be told, I and others I knew never just put a single round into a target. Not emptying magazines in one gloriously satisfying burst of sheer, barrel melting mayhem, but two or three (or four or five, depending on how amped up we were) quick shots on semi. I think the cartridge is hamstrung by the projectile design, and the whole Hague Convention limitations that force the FMJ to be used. I think the engineers could maybe focus on re-designing a better projectile, borrowing from the data available from the hunting community (as they test their stuff on live targets every year), while still adhering to the Hague Conventions. Or just ditch the Hague Conventions, as how is it more humane to get shot by a non-expanding projectile rather than blown up by an IED?

[Raellus]

I heard an interview on NPR's "Fresh Air" recently with the author of a relatively new book called, IIRC, The Gun, about the history of the AK-47. He talked a little about the development of the M-16 and apparently the government ran secret tests on human cadavers (purchased from India) back in the early '60s to compare the effects of the 5.56mm round and the 7.62mm x 39 round. From what the author said, the conclusions were that both rounds equally messed up flesh and bone. In other words, there was little qualitative difference between the damage inflicted by the 5.56 and 7.62 x 39. I can't remember how the author put it but it was rather amusing. Something like "Well, both rounds did what you'd expect to a human skull. The 5.56 destroyed it and the 7.62 destroyed it. You couldn't really tell the difference. Either way, you ended up with a shattered skull."

The government covered up the tests because they didn't think that the American public (or the int'l community) would react well to the nature of the tests. Apparently, some info did leak out and that lent to the early and inaccurate stories about how the 5.56mm was some sort of super round that could kill with a limb shot.

[Legbreaker]

Originally Posted by Gorbag

But, truth be told, I and others I knew never just put a single round into a target. Not emptying magazines in one gloriously satisfying burst of sheer, barrel melting mayhem, but two or three (or four or five, depending on how amped up we were) quick shots on semi.

Which rather defeats the idea of the 5.56 allowing more rounds to be carried and thereby increasing the combat stamina of the soldier...
7.62N - one shot, one kill. You might only be carrying half the ammo, but you don't have to waste time (with additional shots) and ammo making sure the target stays down.

[Raellus]

So, back in the '80s, the M16A2 eliminated the full-auto fire capability in order to prevent "spray and pray" ammo wasting, correct?

Has full auto fire capability been brought back for the M4 and the current version of the M-16? It seems to me that I've seen Iraq and Afghanistan footage of soldiers firing M4s on full auto and, IIRC, U.S. Marines firing "long" M16s on full auto. Come to think of it, in rereading Generation Kill and Thunder Run, it was strongly implied by both authors (neither one of them soldiers) that M4s were fired full auto. Can anyone definitively answer this question for me?

(I'm feeling too lazy to do the research myself right now...)

[dragoon500ly]

Colt is introducing a new combat rifle prototype, it will use a short barrel and the 5.56mm round for urban fighting and if the infantryman needs to make a long range shot, he just pulls out the longer barrel, installs it and slaps in a magazine of 7.62mm...

I had to set down and read the article three times. In the quest for a more lethal round, Colt, the premier firearms maker, actually is trying to sell a rifle that will have the PBI loaded down with a second barrel, and a set of different mags in a different caliber.

DEAR GAWD!!!!! The sheer brillance of this idea has knocked me senseless, its the perfect answer! And it can be so used with every other weapon systems. Just think, the SAW gunner gets to hump 5.56, as well as an extra barrel and 7.62mm and for those special occasions, he can hump a third barrel and a couple of belts of .50!!!

And forget the debate about 20mm, 30mm or 40mm grenades. Let the grenadier hump three different barrels, not to mention three basic loads!

AND the PBI can also carry the full set-up for Land Warrior as well, after all, whats an extra 30-40 kilos?!?

Engineers, whenever they design field gear, they should have a veteran whose had to hump the latest, standing right behind them...holding a sledge hammer!

[Snake Eyes]

My project for the winter is to build an AR chambered in .458 SOCOM. I'm sure there's no shortage of opinions on that.

[HorseSoldier]

The M4 and M16A4 used by the conventional US Army and USMC respectively both retain the three round burst (tech fixes for training problems are always dubious to me). The M4A1 used by SOCOM is full auto, as is the M16A3 issued in limited quantities by the USN (and the SPR as well). The Army is finally starting to switch over to the M4A1 for non-SOF units within the last few months.

[waiting4something]

Originally Posted by Snake Eyes

My project for the winter is to build an AR chambered in .458 SOCOM. I'm sure there's no shortage of opinions on that.

Yeah, here's my 2 cents get a reloader, or plan on having a nice wall piece. I know a guy who has a .50 Beowulf AR and that's what he found out. The ammo is rare and cost like 4 bucks a shot. It's cool for close up stuff and will kill anything on this earth I'm sure. But, I would avoid rounds like those unless you are going to use them on living things. The ammo just cost to much for shooting paper. That's what stopped me from getting one. Impressive rounds, but good lord that's a lot of money to punch a hole in a paper target.

[HorseSoldier]

I had to set down and read the article three times. In the quest for a more lethal round, Colt, the premier firearms maker, actually is trying to sell a rifle that will have the PBI loaded down with a second barrel, and a set of different mags in a different caliber.

The PBI mostly rides these days in up armor humvees or MRAPs or whatever (and yet they get so very upset when I point out that the US Army should probably roll the 11 series MOS's into 19D, since they're just dragoons . . .). A lot of our ODAs rolled with multiple uppers for their M4s, since those were purchasable at the unit level with op funds, but I doubt the Big Army would spring for everybody in an infantry unit to have multiple caliber components for their weapons and don't think it's likely that they'd ever select 7.62x51 for theater wide use or anything. Where I do think they'd get some economy of scale would be common parts shared between general service rifles and DMRs/sniper rifles, as well as reducing retraining requirements for guys transitioning from general to specialist weapons (rather like the M4/M110 allows at present).

My project for the winter is to build an AR chambered in .458 SOCOM. I'm sure there's no shortage of opinions on that.

I've been thinking that one in 458 in an SBR format (12" barrel) would be a great bear gun for up here in Alaska (Teppo Jutsu has one on their website with an even shorter barrel if I remember right). Ammo price would be way up there like waiting4something said, but you could build relevant muscle memory shooting 5.56 (and since the lower would be the registered SBR and you can specify multiple calibers on the paperwork, a matching 12" 5.56mm upper would be good to go) and just do a little familiarization with the big bore rounds to get a feel for how the recoil effects handling and split times and such.