Design od shotgun or rifle mics ?

[MottledGreen]

Hi, I am looking for info for designing a shotgun or rifle mic assembly for a school
project.
Specifically, long distance outdoors with human voice / speech frequencies.

Mic output would go to an existing pre amp.
Any info on construction materials, dimensions, mic insert types would be
much appreciated. I realise that some dimensions would be based on the wavelength of the desired frequency range (50Hz-6Khz), which are easy to work out using the speed of sound formula, but which dimensions ?

I have a design for a rifle mic constructed in an organ pipe style, but are unsure of the construction material to use for this or the shotgun mic. Metal or PVC pipe ?

The mic I was intending to use would be a condenser type but any advice on which and how to mount it would be appreciated.
No FAQ or Web info available; I just spend 12 hours looking !

 

[Kelly Holdridge]

Consider a parabola reflector. I suppose you might rig either a umbrella (coat w/ shellac?) or one of those round sled things (i'm in alabama and texas--I have NO idea what they're called). Find a geometry book and figure out the focal point, and put your mic there, facing opposite your target audio. You may be able to just headphone the audio and find the sweetspot without using the math. Just an idea.