For those not overly familiar with things ballistic, my own elementary understanding:

Yes, our people fire .22 cal. bullets, but they're not like the one you shot at summer camp when camps still did that. The military version is the same diameter, but the bullet is longer, and thus heavier.

A little physics. The speed something hits something has much more effect on the damage done than the weight of the the thing doing the hitting.

The idea behind the military .22 cal is that you get this longer, lighter, narrow bullet moving really fast, and it will tumble the instant it hits its target, and that does a lot of damage to the target. The advantage is you get more individual bullets to fire, that will still be lethal, but will weigh a lot less than heavier ammo.

But the key is that those bullets must impact at high velocity to have a lethal punch. A HUGE factor in producing that velocity is the length of the barrel. That is because you have to give the hot, expanding gas TIME to push on the bullet moving down the barrel to get it up to speed. Shorten the barrel, and you lower that speed. Lower the speed too much and you have -- almost literally -- a pea shooter.

Since the resurgence in popularity of the almost 100 year-old Colt 45 Model 1911 pistol, I'm wondering, Bob -- not that I think such a thing would ever happen -- how much of a WWII Thompson submachine gun would actually have to be made out of heavy, machined steel if someone were to update it as a modern assault rifle?

I know, I know, but one can dream.

The Afghan Mujahideen defeated the Soviet empire with a mix of Soviet weapons,Lee Enfields, and God help them even a few old Martini rifles left by the Brits in the 19th century. If the US can't win over there it won't be because the M16 is an inferior weapon(I'd go with an M14, but that's another post). We really need to be asking ourselves what the hell we are doing over there, and if inserting tens of thousands of troops is going to do anything more than piss off the locals, which is something you REALLY don't want to do. Just ask Alexander the Great, the Brits, or the Russians.

My absolute favorite weapon from 1965 - 1968 was the .50 cal. mounted on my APC - what a feeling of power - and special fun with tracers at night. The next favorite was my .45 cal. pistol, but alas you had to be close to the target, but you knew he wasn't getting up! In the beginning we used the M-14 - which was an excellent weapon - ( see the post above) but not suited for a lot of moisture, mud and gunk, but may do well in the desert and mountains - don't really know - it's been a long time.

Bottom line - it is a MASSIVE UNFOGIVABLE SHAME that our military don't have the BEST weapon on the planet - end of story - no excuses.

With current leadership in D.C. I doubt it will get any better.

I started Basic Training with am M-14 before transitioning to an M-16. We used to insist that Mattel was the contractor for the M-16. Luckily, within a year, I had transitioned back to a pair XM-21s that traveled with me for the next seven years. I have noticed that the M-21 systems are still around and in high demand by special operators. The 7.62 NATO packs a better punch (especially as range lengthens) is less affected by brush. Personally, I think an M-4 is for clearing urban rooms, but for that I don't see an advantage over an HK MP-5. Disclaimer; I have never handled an M-4.

Just getting away from the Direct Gas system would do wonders. Yes, it is more accurate at long distances, but even in the Ashcan, it isn't that big a deal to the average troop.
A sustained fire fight will cause the thing to stop working. It will happen, and the fighting there (as opposed to Iraq) is often longer in nature. The Muhj prefered the AK to the AKM because they could use the .22 ammo if needs be in the 7.62. No it was not accurate, or as fast, but lead went down range.

A 6.5-7mm round would do wonders in QCB, and something that still allows the larger amount of ammo per pound is a good idea.
The AR being 40 isn't as big a deal as some of the "replacements" are AR's with improvements. Piston designs that, as with the barrels for a more effective size round, can be used on existing lowers (not that saving money is ever an important thing to procurement processes). Some of the Spec Ops folks are still using a few M14s, whiuch is based on the even older M1 Garand. But, like the 14 was an improved version of the 1, the A4 is something of an improvement of the M16. But they didn't (in my opinion) improve it enough.
The Ar in .458-Socom with a Piston actuator is ideal for room to room, but the thing hold what, 10 rounds in a regular mag? The 222/223 is only good for up to a 7.62/.308 and reliably operate, and the bullet is rather short then. The 6.8 was brought about to try to optimize the size and length and still reliably feed and headspace (there is a wildcat .338/223, but headspacing is a nightmare). Sadly, every alternate round is going to be lacking somehow, but I do think just going to the 6.8-spc and piston uppers would allay much of the troubles we have.

Eugene Stoner followed the AR-15 design with the AR-18 which fixed almost all the problems of the earlier design, gas piston design, folding stock, flat top receiver. receiver of steel rather than pot metal. The Govt. was not about to admit to a second mistake after the reliability problems of the M-14 just a few years earlier and have plowed on with an inherently bad design.

I used an AR-18 extensively in the '70s and it was dead solid perfect.

The M-16 family of which the M4 is a recent variant has much to recommend it: Light weight, great inherent accuracy, exceptional ergonomics, very little recoil, substantial quantities of ammunition may be reasonably carried, and easy adaptability to a wide variety of useful accessories. On the downside, however, there are a number of real concerns including:

(1) The gas impingement system is inherently unreliable in combat conditions. It dumps unburned powder and fouling directly into the chamber and action of the weapon. In clean, ideal conditions, it works fine; in combat, it requires substantial maintenance and may be deadly.

(2) The 5.56 cartridge, particularly in military ball configuration (full metal jacketed bullets), can be quite effective if fired from the standard 20" M-16 barrel, but the M4 is some 4" shorter and the resulting loss in velocity substantially reduces the effectiveness of the round on human beings. The round has never been an effective penetrator of cover. Of course, the larger and heavier the cartridge, the fewer rounds may be carried, so this is always a trade-off.

(3) The weapon is not robust and can be rather easily broken if misused. You don't, for example, want to butt-stroke anyone.

For civilian uses, including police work, the current weapon is a near ideal. Of course, this is true because, apart from the many good qualities of the weapon, few civilians will be called upon to fire hundreds of rounds on automatic, or even semi-automatic, in a very short period of time without maintenance.

The trick here--if keeping the AR configuration is the goal--is to retain the many positive qualities of the weapon while including a gas piston design (and a few other smaller refinements). H&K, Ruger and others have done just that in the AR configuration. A more effective cartridge without excessive weight might also be possible, but the easiest solution might be a bullpup design like the Israeli Tavor that would allow all of the positive qualities of the M-16, including a 20" or longer barrel, in a package no longer than the M4. With a revamping of bullet design with the goal of improving lethality without relying exclusively on high velocity, this might be an optimum solution.

Lot of contraversy here about the M4 and other individual weapons used by our Military.

I know that the M16 I used forty years ago was not reliable but that was just what we experienced in our unit. We favored carrying AKs when we went out (Long Range Patrol) because if we had to fire our weapons (which was a no no) they wouldn't know the Americans were around.

The U.S. Military is not going to just up and replace the M4 all at once, it is going to have to be dragged kicking and screaming replacing them a few thousand at a time starting out with our SOF, Rangers and selected Marine units.

All you will ever need to know and more at this link:

FN SCAR

Papa Ray
Central (used to be West) Texas

The M4 and M16 need to be replaced IMMEDIATELY. They simply do not meet acceptable reliance and stopping power standards. Both the 5.56 and 7.62 have too many shortcomings. As does the 6.8 round. The great thing about the 5.56 is that it's small, compact, light weight and accurate. The great thing about the 7.62 is that it hits a lot harder. But where the 7.62 fails is in long range accuracy, weight and size. The 6.5 Grendel round is BY FAR the best round on the market since it combines the accuracy of the 5.56 with the stopping power of the 7.62 round. It shoots further than the 5.56, 6.8 and 7.62, it shoots more accurately than all 3 with a much flatter trajectory and it has stopping power almost as good as the 7.62 round. We need to build a rifle around the 6.5 Grendel ASAP. It should be extremely reliable, extremely durable, extremely accurate, extremely comfortable to use, extremely light weight, extremely customizable and not too expensive. I haven't seen a gun on the market that quite meets all those requirments so we need to get a competition going immediately between gun manufactures to produce those rifles. They should make an affordable semi-automatic version as well so the civilian market can eat them up and make it more lucritive to manufacture them. GIVE OUR TROOPS THE BEST. THEY DESERVE IT.

Also let me add that there are indeed AR-15 style rifles that already meet most of those standards if not all of them. But I've never personally handled one so I don't feel comfortable recommending them. But it very well might be that this rifle is already ready to go so we should start filling out large orders for them. The military should be on top of this anyway. If not then shame on them.

Another thing they should seriously consider is adding bullpup ammo loading into the gun. It allows the gun to be much more compact without sacrificing accuracy or bullet velocity. It might look strange, feel strange and be a little slower to load but our soldiers will get quickly used to it just like the British and others have. It will also allow for better urban combat and vehicle combat capabilities.

We need another John Browning. No one ever complained about his weapons jamming or lacking effectiveness, and we still use the Ma Deuce .50 caliber, which works just fine.

So the AK-47 stopped the Russians and fought us to stand still.... Why reinvent the wheel?
Just convert to the ak-47, much cheaper, reliable and seems to work well in a combat situation. How often do we engagae with small arms at long ranges anyway? Introducing a new style of weapon and a new cartridge will in our political arean will drag on for decades. Do we always need the most expensive stuff?

The problem is the direct gas impigment system. After 200 rounds or so, it becomes less and less reliable. It is also sensitive to dust and dirt. This has been a continual problem since Vietnam and has not be solved. An AK variant in 5.56 would be a real solution.

Get 'em all AKs. Problem solved.

"Bottom line - it is a MASSIVE UNFOGIVABLE SHAME that our military don't have the BEST weapon on the planet - end of story - no excuses."

Yes it is sad that we can't have the best that money can buy. However, being a former military guy, I can understand it.

Say you can buy a decent rifle for a thousand dollars, or you can buy a great rifle for fifteen hundred. You, buying one rifle will probably go for the fifteen hundred dollar rifle. But if you are buying a million of them, you will likely go with the thousand dollar rifle.

It is better to have everyone have a decent rifle instead of a few people having a great rifle, and everyone else a crappy one.

The major problems with the M4 are simple. Shorter barrel means lower velocity. Lower velocity means that the projectile drops below the 2400 ft/s mark where it fragments inside the body. It also means lower barrel pressers that cycle the rifle. Lower barrel pressures mean less functionality.

Now, if you would all think back about six years you may remember public outcry that our troops had rifles that were too long, and couldn't operate as well in buildings, or getting out of vehicles.

So what does the military do? They go with a shorter rifle.

Blame yourselves America.