Army seeks gun industry help on M4 carbine...your thoughts?

LTC Paul Labrador,
That sir was an opps AK 74 it is.

LTC Paul Labrador,

Sir,
The most important thing is clearly shot placement when hunting, even a .22 will kill a deer with the perfect shot. Now as far as the weapon used I have seen some one shoot a mule deer with a 22-250 which uses the same caliber bullet as the 5.56. He shot it 3 times before it went down with each round knocking in animal down and then getting up again, he was trying for a neck shot. The round had left a rather small exit wound. It of course would have died from the first shot but would he have found the animal?

The deer that I have shot for the most part have been with a 25-06 or a .270, both are based on the 30-06 case. The result of the bullet impacting the deer with these rounds has killed the animal quickly leaving a larger exit wound than what a .22/5.56 caliber round does. When dressing out the animal the body cavity is usually devastated from the round passing through, lungs collapsed etc. Most either drop in the area where it was shot or run a short distance perhaps a few hundred yards. I have had to chase down a few deer and that was my fault, once again shot placement.

I have also seen people take reckless shots and wound an animal and never find it, that comes down to experience or lack of respect for the animal. This is a sure way not to get invited back to to hunt!

As far as hydrostatic shock is concerned a fast small round will not produce nearly as much as a large slow round like .45 ACP or shotgun slug. Shoot a gallon jug of watter with a .22 then with large slow round like .45 ACP or Colt .45, on can see what happens to fluids when put under pressure; as we all know liquids do not compress so they have to go some where.

Dr Martin Fackler did his study during the Vietnam war, a later study was done and countered his findings. It is interesting that the first studies that suggested hydrostatic shock could damage organs were made when much larger caliber weapons were in use. 30-06, .303 British, 8mm mouser, etc.

“Dr. Randall Gilbert describes hydrostatic shock as an important factor in bullet performance on whitetail deer, “When it [a bullet] enters a whitetail’s body, huge accompanying shock waves send vast amounts of energy through nearby organs, sending them into arrest or shut down.”[62] Dave Ehrig expresses the view that hydrostatic shock depends on impact velocities above 1,100 ft (340 m) per second.[63] Sid Evans explains the performance of the Nosler Partition bullet and Federal Cartridge Company’s decision to load this bullet in terms of the large tissue cavitation and hydrostatic shock produced from the frontal diameter of the expanded bullet.[64] The North American Hunting Club suggests big game cartridges that create enough hydrostatic shock to quickly bring animals down.” (wikipedia)

Velocity is the prime factor for "hydrostatic shock". Using your water jug analogy, a .22LR shot into a jug will not cause much of a splash. Shoot a 5.56mm into that same jug, and it blows the jug apart. While both are .22 rounds, the 5.56mm is going almost 3x faster. Velocity is what allows a rifle round that weighs half of that of a pistol round to create devastating wounds.

Now, we also need to clarify what "hydrostatic shock" really means. While we all know that there is hydrostatic displacement (and the associated stretching and tearing of tissue) due to the incompressibility of water. That is not disputed. However, what most people refer to as "hydrostatic shock" is the stunning/knockout effect of bullets. That is theoretically caused by the KE transfer from the bullet to the body causing a spike in the blood pressure of the target which activates baroreceptors in the body which in turn can cause a reciprocal drop in brain perfusion.....resulting in loss of consciousness. That effect has not consistently been proven to exist, as evidenced by game animals bolting and running for a bit before bleeding out, even after taking a mortal hit to the CV organs. Again, why the emphasis on creation of a large permanent wound channel and shot placement into vital organs. If you can get a CNS hit, even better.

Size matters or in this case mass if we look at standard 62 Gr 5.56 round vs. 100 Gr. Round at the same velocity the results are significant.

Energy = .5 * weight * velocity^2 / 7000 / 32.175
7000 is grains per pound, and 32.175 is acceleration due to gravity.

62Gr 3100fps = 1322.72 Foot Pounds Energy
100Gr 3100fps = 2133.42 Foot Pounds Energy

The more massive an object is the more KE will be delivered if all else is equal in this case about 800 foot pounds.

It could stand a few upgrades, not the least of which simply being Magazines, but I do agree.

Most important upgrade needed, ambi controls. I'm a lefty and struggled until I came to a community where I could outfit my long gun with an ambi selector lever and mag release. The bare bones mags work fine, the problem comes when units don't accept the fact they are EXPENDABLE and run them 5 times longer than they should.

1SG (Join to see) , I wish that more of the people in the Regular Army could be as smart about that kind of thing as the Special Ops groups.

You would figure in over 50 years of use the DOD would spring for a simple and low cost upgrade for us lefties.

Agreed. Most of that should be in a ruck or a deployment box until needed.

They are issuing short barrels to almost all the troops now, from what I am told.
They really need to get away from that. It doesn't provide a realistic weapon for exerting combat power over an AO.
The 18" barrel with mid length hand guard and gas system works very well for range, accuracy and reliability of action. It is also a nice compromise between the 20" barrel and the 16" barrel when it comes to compact carry and weight savings. There is very little justification, that I can believe, to have a rifle with a barrel less than 16".
I like the idea of a piston system, but for most soldiers is is not worth the extra cost and weight. Piston systems can also reduce accuracy as they affect the barrel harmonics to a greater degree.
Just my two cents.

I'm with you on that.

Something as simple as better Magazines solves that issue about 90% of the time. Magpul Pmags solve it with follower design and honestly, even the steel mags do pretty well if they aren't worn out, which I would guess a majority of the inventory is.

Also the ammo itself. There is some ammo that is lacquered to prevent tarnish. When fired, the lacquer melts and it can cause feeding issues in the weapon. We had it happen with an AR-15 when we were at the range for fun. It also leaves a nasty coating inside the barrel.

GI ammo is not lacquered. Cheap Soviet stuff typically is as they are steel case and need the lacquer to not rust.

So the M4, all of SOCOM still uses it, the larger SOCOM units like us in SF and the SEALs use a plain Colt M4, mostly with an upgraded upper that has a free floating barrel. The smaller footprint SOF units have an M4 as well, just an upgraded one. All the HK 416 is an upgraded M4.

1LT William Clardy I'm aware of the meaning of it all, and I'm not at all saying that you're incorrect about it...I just disagree with the core of the definition. My disagreement would actually have to date back to the first person to officialize the term with it's associated verbiage in relation to its context.

All I'm saying is that something with a 50% chance of a fragment striking a man-sized target within a given range doesn't meet with my definition of effective.

Sure, nothing is 100% but if it were, say, a 75% chance of producing a wound requiring medical attention within a given range, THEN we would be beginning to approach my definition of effective.

SGT Richard H., it's the difference between retail and wholesale war-making.

The 50 percent is an arbitrary cutoff, basically just saying that you're more likely than not to score a hit. You can make a good case for changing that threshold to 75 percent, just like I have always been aware of very good arguments for redefining the target shape to represent a kneeling man, although that would add the complication of whether you use the frontal or side profile (makes a huge difference in exposed target area).

I kind of like your idea on the targets! My vote goes to both profiles, randomly presented.