Something else to model

[Nemesis Lead]

In the latest Iraq war.....US troops (particularly in the Army) are using M4 with 14 inch or shorter barrels. M16's were originally designed with 20 inch barrels and the Marines are still using M16s with 20 inch barrels the majority of the time.

Why does this matter?

While the M4 is more handy now, the shorter barrels have reduced muzzle velocities from 3100 fps to 2600 fps. Short barreled weapons are far less lethal as a result. More specifically, 5.56mm bullets kill primarily by inflicting grievous wounds due to the outrageous spalling of the projectile at high velocities. At 2600 fps there is far less spalling and our troops are again complaining about the effectiveness of the 5.56mm round.

My question is....will this be modelled? An M16 with a 20 inch barrel and an ACOG (Marines) on top is VERY different from an M4 with a 14 inch barrel and an Aimpoint on top (Army). The Marines have a rifle that is better at range and more lethal, but less handy. The Army is a weapon that is good in close combat (although many question the M4s lethality).

How might these differences be captured?

[Homo ferricus]

i would think that battlefront would leave the muzzle velocities alone and just set the M16 to be more effective at a longer range, indeed due to faster muzzle velocities and the use of the 4X ACOG site, but then again, it will be a while before the supposed Marine Corps expansion comes out.

[Sixxkiller]

Hi Nemesis,

The reason for the shorter barrel isnt just for doing more damage to the human body in close engagements, it also gives a distinct advantage in homes as houses in Afghanistan (Dont know first hand about Iraq) are quite a bit smaller in the entry way (door or holes blown in the walls) and it takes less time to bring the barrel on the target.

Also I can see less over penetration possibly keeping non combatant casualties down.

[John Kettler]

Sixxkiller,

Did I miss something? How does the shorter barreled M4 do more damage, not less, than the long barreled M16A2? I certainly agree with your other two points, though.

Regards,

John Kettler

[dixon_el]

Reducing the speed of a round decreases the shoot-thru effect. If the round doesn't go thru the target all energy is expended on the target. That and size are what makes the low-speed 45cal round so damaging to the fleshy parts of the body.

In Viet-Nam many soldiers quickly discovered that the small, high speed M16 round was not as effective at close rate as many of the older larger and slower rounds at stopping close range targets.

A lesson the military looked at and discarded because NATO wanted a uniform round.

[Nemesis Lead]

Slower rounds do less damage, not more.

However....one interesting effect is that slower rounds can often penetrate deeper into tissue than faster rounds (penetration and damage are not the same).

The reason is......faster rounds will spall and yaw more and then penetrate less as a result. FACT: a 7.62mm X 51mm ball round penetrates more moving at 2400 fps than it does at 2750 fps. Why? At 2400 fps the bullet will not turn over on its side or break apart both of which decreases penetration siginificantly (but also increases tissue trama).

Also--5.56mm rounds will penetrate less than 9mm rounds moving at less than half the speed (but the 5.56mm round will cause far more gruesome wounds).

Wound ballistics can be very counterintuitive!

[MikeyD]

BFC had said one of the major event-driven changes they've had to make to the game since its inception has been swapping out the M16 for the M4 in Stryker Brigade units. Remember when the little guy in the masthead lost his M16? And they've mentioned the slight range reduction too. I'm curious about whether - or how often - a plain-Jane M16 will show up in the game now [EDITED: M16's not on BFC's weapons list in the 'Syrian Sniper Rifle' thread.] I'd imagine a big difference for the Marine module would be all M16 use. It'll be interesting to see if it makes any discernable tactical difference.

The phrase 'slight range reduction' keeps on popping up in official records with seeming emphasis on 'slight'. But a mv drop to some 83% of that fired from an M16 barrel seems significant, especially for a lightweight bullet. But sometimes 'less' can still be 'plenty'. You can't get any more dead than dead.

[ November 15, 2006, 09:58 AM: Message edited by: MikeyD ]

[Sixxkiller]

Slower rounds do MORE damage to the human body when your target isnt wearing body armor as it has a better chance of bouncing off bones instead of penetrating and going through. But all this depends on what type of weapon, range to target, type of bullet, air temp, place bullet hits, and how much they have prayed to Allah lately.

But lets face it a M-16/M4 system in a CQB environment even with a shorter barrel isnt the best choice anyway. The bad thing in especially Iraq is that CQB can quickly turn into something else.

Originally posted by Nemesis Lead:

Slower rounds do less damage, not more.

However....one interesting effect is that slower rounds can often penetrate deeper into tissue than faster rounds (penetration and damage are not the same).

The reason is......faster rounds will spall and yaw more and then penetrate less as a result. FACT: a 7.62mm X 51mm ball round penetrates more moving at 2400 fps than it does at 2750 fps. Why? At 2400 fps the bullet will not turn over on its side or break apart both of which decreases penetration siginificantly (but also increases tissue trama).

Also--5.56mm rounds will penetrate less than 9mm rounds moving at less than half the speed (but the 5.56mm round will cause far more gruesome wounds).

Wound ballistics can be very counterintuitive!

[Nemesis Lead]

Originally posted by Sixxkiller:

[QB] Slower rounds do MORE damage to the human body when your target isnt wearing body armor as it has a better chance of bouncing off bones instead of penetrating and going through.

[acrashb]

Originally posted by Nemesis Lead:

[Sixxkiller]

acrashb wrote: "So M4's work just fine at CQB ranges. They also work pretty well past that, since a bad guy at 100+ yards doesn't need to be dropped as fast, relatively speaking, as a bad guy close."

Well this is debateable as for my time in Afghanistan I was deployed with the M4A1 SOPMOD and while it was ok at CQB ranges it has its problems at range, but this is essentially due to the light weight of the rounds and the short barrel. Also its moveable parts break down constantly because of the gas pressure confined to such a short barrel. The worst problem was with the barrel and forend heating up too %^$%& fast. It should be relegated to rear unit s IMO. Well w/o the little goodies anyway.

[RMC]

Originally posted by Sixxkiller:

It should be relegated to rear unit s IMO. Well w/o the little goodies anyway.

I thought it was very ironic that the line infantry units were getting the carbines while the rear units retained rifles. In WWII the issue pattern was the opposite.

[acrashb]

Originally posted by Sixxkiller:

Also its moveable parts break down constantly because of the gas pressure confined to such a short barrel.

The original question was about terminal effects, but yeah, the shorter barrel means a larger gas port (because the pressure doesn't last as long, you need a bigger port to keep the total volume the same) means faster bolt speeds means extractors and other bits and pieces are working beyond original design tolerances (so you get workarounds like rubber donuts added to the extractor spring). The guys I know are contractors - they have typically brand-new or well-maintained gear, and they don't report any problems.

[J Ruddy]

Well... I know it's shocking, but I have an opinion on this...

As a hunter I *know* that (Contrary to some people's opinions) the most common cause of death in a large animal is shock. Whether it is a 1 oz 12 Gauge Slug at 1100 fps or a 160 grain 7mm Mag at 3000 fps, the goal of the ammo manufacturer is to cause enough damage to put the target into severe shock causing death.

White Tail Deer Bucks Average 150-220 lbs so I think they make a good choice for drawing a parallel with military targets.

There are a number of big bore fanatics who use 44 Mag, .45/70, .444 etc... on deer and there are the guys who use .243 (a necked down high velocity .308 / 7.62 x 51) Obviously these are very different weapons that kill in different ways. (OK, I know, 30-06, .308, 7mm mag, 6.5 etc.. are popular too but lets look at .45/70 vs .243)

The .243 will convert the kinetic energy of a rapidly travelling nice small efficient bullet into a large flat-ish piece of copper & lead which causes massive tissue damage and trauma.

The .45/70 is already a large diameter bullet and while it will mushroom to become even larger, the bullet design will waste less energy to do so.

So a low velocity larger bore round *can* cause trauma as well a high energy smaller bore round and vice versa based on efficient bullet design. The hv round wins in things like bullet drop and range, while the slower round wins in things like 'twig deflections' and not accidentally shooting your neighbours dog 1200 yards away...

I don't think that FMJ rounds use any of the advanced expanding bullet designs that we can get away with hunting. So the 5.56 NATO, a small light super fast round that will fragment, yaw etc... was developed (roughly based on the civilian .222). Soldiers could suddenly carry much more ammo and supposedly do the same job as the 7.62 when it comes to causing trauma.

So why is it no one in their right mind hunts deer with .223 rifles?

One guess is that hunters are more humane than military weapons designers. The deer don't have field hospitals and medics to patch them up. Another is we don't like fragmentation. (At least I don't, the thought of digging through a carcass to find 17 fragments of a shattered round doesn't appeal to me.)

Anyways, will a 500 fps drop make a big difference in a FMJ 5.56's terminal performance? (That number seems very high, the average rule of thumb is 50fps per inch)

If it were an expanding round, then yes, absolutely a 500 fps loss would be a terrible thing. You need the kinetic energy to mushroom the round and cause the most trauma. But a non mushrooming FMJ? I guess it won't fragment as much, though I believe fragmentation in a high powered rifle round is normally associated with *very* high velocities not seen with a 5.56 at more than 100 yds even with a 20" barrel.

If you check the ballistics of the Remington UMC 55gr FMJ round, from a 20" barrel it loses around ~500 fps at 100 yards and an additional ~400 fps at 200 yds. So if you lose 500 fps from the get-go you're basically cutting 100 yards off the effective range for the weapon. Given a 16" barrel I don't think I'd want to engage at more than 200 yards anyways. At 200yds and ~1600fps the 5.56 will still be dangerous enough to ruin my day.

Still, if it came down to my life, I'd prefer the heavier, larger 6.8SPC in the 16" barrel, thanks. It's the old claymore versus rapier thing, you know what I mean?

Jim