Slowburn
Operationally this has got to cost more than a machine gun (up to 30mm) or laser based system.
Jeff J Carlson
I seem to remember the Navy's CIWS could shoot down incoming shells ...
Maxim Chanturiay
The concept is great. Defending troops and destroying enemy's highly cost ammunition at the same time
Dekarate
mortar rounds are dirt cheap not expensive
Marc 1
Slowburn: Do you realise the difficulty of destroying a mortar round in its terminal phase using machine guns? Frankly extremely difficult. That is why the best possible light cannon to use for the job would be a 20- 30mm CWIS - usually a gattling cannon design.
Which brings me to Jeffery's point - if the weapon has a cyclic rate of fire of say 6000 rpm and you fire a 3 second burst per mortar round engaged, that's 300 rounds fired, only a few of which may hit. What happens to the other 290 odd rounds? Have you considered the collateral damage to surrounding populations and forces?
Mortar rounds as Dekarate has pointed out are very cheap - as are mortar tubes. This is a very expensive system, BUT hopefully the number of missiles needing to be fired would be less than 5 to 10 (as that would be as many rounds as the mortar team would be able to get away before counter battery fire guided by using Mortar locating radar such as the AN/TPS 49 will quickly wipe out the offending tube and crew. Even insurgents aren't stupid - if none of their rounds get though, and they are wiped out they will be forced to use alternate methods which may be more expensive and or difficult to enable.
Nairda
I second Marc1's comment. Many bases are surrounded by civilian population. 30mm rounds falling back down at terminal velocity can kill people.
Laser/energy based systems are the long term solution, but may be limited for multiple projectiles unless the directed energy is sufficiently high.
For the short to medium term, a battery of mini missiles provide a solution.
However all these systems can't defend against a directional air burst mortar that sends a narrow cone of dense shrapnel towards the intended destination. Someone needs to invent enegy shields. :b
Slowburn
re; Marc 1
Hitting a 75mm wide target at a range of 500m with a 7.62mm X 51mm (308) round is not difficult. Using a computer controlled, radar guided, machine gun that is in a powered stabilized mount to hit a target on a ballistic target does not seem an insurmountable task. The smallest gun I would use is a 12.7mm (50BMG).
On a conventional battlefield like WWII making the the bullets come down on enemy territory (Avoiding civilian populated areas) or in cleared fallout zones. However bullets do not have to come down with lethal force. Making bullets that will develop on unaerodynamic tumble or placing a tiny explosive charge that will reshape the projectile to generate aerodynamic high drag is easily doable and I see no real difficulty in making bullets that burn to dust before falling back to earth.

flink
Have any of you ever been on the receiving end of an artillery barrage? You need a few truck loads of these little rockets. It's a great idea, but too expensive to implement for real-world use.
Ron Johnson
"Hitting a 75mm wide target at a range of 500m with a 7.62mm X 51mm (308) round is not difficult. "
But hitting a 82mm target at 500m when it's moving at a high rate of speed is a STUPENDOUSLY difficult task. Recall WW2 where anti-aircraft guns had to shoot *thousands* of rounds in order to hit air planes (obviously *much larger* than mortar bombs).
KMH
Dunno whether this is a good idea or not, but I'd add a chip to plot the original source and a device to flatten it while I was at it... Hey - maybe use whiffle bullets? High rate of initial speed and slow down quicky at a set range? Or "bird shot"?