Flechette Rifles and Salvo Fire

[Nightcrawler]

*Sigh* This post was going to be much longer and more detailed. But again, I forgot to go ctrl-C, and when I hit "POST" it asked for my name and password, thusly deleting everything I had typed.

Damn it.

Anyways, let us consider the Steyr ACR. It was the cumulation of several flechette rifle and salvo fire concepts, that go back to the 1950s vintage Special Purpose Individual Weapon program.


Steyr ACR, caliber 5.56x45mm Synthetic Flechette


Steyr 5.56x45mm Synthetic Flechette ammunition

THe HK G11 caseless rifle, with its high-cyclic burstfire, was an attempt at a salvo weapon system. But with ballistics similar to 5.56mm (50-something grains at around 3000 fps), it wasn't really a flechette weapon.

The Steyr catridge fires a roughly 10 grain projectile at extremely high velocity. According to Steyr literature, it's still going 910 meters per second (roughly 2980 fps) at six hundred meters.

This would indeed make long ranged shooting easy, as the rounds would be on target so quickly that windage and drop compensation needs would be minimized.

More info on the Steyr ACR can be found HERE.

So I pose the question to my fellow High Roaders: Do you think the high-velocity flechette rifle is a viable concept? Would you see military or police forces equipped with rifles similar to the Steyr ACR? Would you yourself use one?

What kind of terminal effectiveness will a 10-grain projectile have, even at that velocity? What kind of thick or mulitple barrier penetration would it offer? 62 grain 5.56mm rounds fragment going through the wall of a house or a tree; would a projectile 1/6th the weight fare any better, even with a thousand feet per second velocity advantage?

 

[Trebor]

So I pose the question to my fellow High Roaders: Do you think the high-velocity flechette rifle is a viable concept?

No. I think the SPIW and ACR programs pretty much showed that flechettes are less effective then traditional centerfire ammo like 5.56 mm. The theoritical advantage of burst dispersion which was supposed to give an increase in hit probability never panned out. The flechettes simply didn't act like they were supposed to. Then there's the problems with the actual wounding power of the flechette itself.

I think enough effort has been thrown down that hole myself to show that the concept is fundamentally flawed.

 

[NMshooter]

As body armor improves the effectiveness of standard rifles decreases.

Two possible solutions are smoothbore fletchette rifles and 7.62x51 Saboted Light Armor Piercing ammunition.

Flechettes do not fragment as far as I know, but the folks that were pushing them for the ACR program tried to sound convincing when they mentioned "fishhooking" of the projectiles. I do not believe this would be a reliable mechanism for increased lethality. A tungsten flechette will not bend, either, and I would think you would want something like that to penetrate body armor.

I personally would prefer a normal rifle, perhaps an AR type rifle in 6.5x38 or 6.8x43, but would carry whatever I felt would be most effective against likely adversaries.

I think police will continue to carry arms similar to what they have now, but I expect military small arms to change dramatically. I also expect there will not be civilian equivalents available.

With powered armor the 40mm HEDP could be the bare minimum needed.

 

[Nightcrawler]

It's worthwhile to point out that even at 5,000 feet per second, a 10 grain projectile generates less than 600 foot pounds of kinetic energy. And it doesn't have enough momentum to create any significant hydrokinetic trauma.

In other words, it's an icepick. Like getting stabbed with said ice pick versus getting hit in the chest with a mattox. They both penetrate, but one hits harder...

As for body armor....don't be surpised if, in the next fifty years, grenade launchers and compact rocket launchers become more and more common.

 

[benEzra]

It's worthwhile to point out that even at 5,000 feet per second, a 10 grain projectile generates less than 600 foot pounds of kinetic energy.

Not only that, but it's not going to transfer much of that energy to the target at all. The rate of energy transfer of a projectile (assuming no fragmenting) is directly related to its hydrodynamic drag coefficient, and since there's no way to get a flechette to either expand or tumble, it's about as low-drag as it can possibly be. Meaning it will exit the target still carrying most of its energy.

 

[Nightcrawler]

I really want a Smart Rifle anyway.

 

[Commissar Gribb]

that's nice...

a rifle with 3 triggers...

talk about asking for a battlefield mishap.