I have heard a PIVAD air defense system fire. It sounds literally like a "Buzzzzzzzzzzzz". You don't get the staccatto of slower cycling small arms - it all blends together into one loud buzz. It really does sound a lot like a chainsaw given gas. The only sound afterwords on some gatling systems is the barrel spin-down and that isn't terribly audible.
I'm imagining that mach+ rounds (even small ones) will be making this kind of 'buzzzzzz' noise.
As for suppressive effects:
How hot are flechettes moving supra-mach? I'm guessing hot. So is every round like a tracer? If so, your suppressive power is pretty good right there.
But they won't be noiseless when you fire them (I can't see it...). They won't be noiseless when they richochet around the target area (remember, we don't *want* pinpoint accuracy for suppressive fire... some historical MGs have actually been too accurate to be good at suppressive fire!) and they'll make one godawful "hissssss" as they snap past or over your head.
Now of course, if you're buttoned down in BD or high tech cbt armour, you'll notice but not have the same visceral reaction.
In short, I think you'll see very hot, possibly flourescing, rounds hisssssing past or over your head. You'll hear them spanging and tinking and whacking off nearby foliage, hard and soft cover, etc. If you're half smart, you'll still be quite supressed.
I'm imagining that mach+ rounds (even small ones) will be making this kind of 'buzzzzzz' noise.
As for suppressive effects:
How hot are flechettes moving supra-mach? I'm guessing hot. So is every round like a tracer? If so, your suppressive power is pretty good right there.
But they won't be noiseless when you fire them (I can't see it...). They won't be noiseless when they richochet around the target area (remember, we don't *want* pinpoint accuracy for suppressive fire... some historical MGs have actually been too accurate to be good at suppressive fire!) and they'll make one godawful "hissssss" as they snap past or over your head.
Now of course, if you're buttoned down in BD or high tech cbt armour, you'll notice but not have the same visceral reaction.
In short, I think you'll see very hot, possibly flourescing, rounds hisssssing past or over your head. You'll hear them spanging and tinking and whacking off nearby foliage, hard and soft cover, etc. If you're half smart, you'll still be quite supressed.