[Lonesome in Massachussets]

Good thing there isn't an inexpensive countermeasure.

[Jimmy Valentine]

Since they are talking
Madonna records, maybe we should double up!

[savedbygrace]

If the numbers here:

http://en.wikipedia.org/wiki/Long_range_acoustic_device

are even close to accurate, you are correct. Those plugs will attenuate by more than 30dB, bringing the sound level at 300m and probably even at 100m down to a manageable level of 60 to 80dB.

[When do we get liberated?]

Want cheaper than that? Wet the filter of a cigarette and stick it in your ear. Works great and I have gone shooting a few times with it.