Water displacement chart?

[Hammer Spring Distillers]

I'm curious if there's any type of chart out there for water displacement on various grains.  I understand it will/may vary somewhat on the grind, but generally speaking.  If I put X pounds of milled grains in my mash tun, and fill it the rest of the way up with water... how much water actually went in there, by percentage?  Sugar is a known variable, but does anyone have numbers for this on corn or other grains?  My very rough guess is that for 250 lbs of milled corn, I'll add about 75 gallons of water to a 100 gallon mash tun to fill it up.  Anyone else ever calculate this before?

[meerkat]

I found some data on the web that gives the particle density of corn as 1.50 g/cm3.  This converts to a displacement of 0.080 gallon per pound. 

Your example of 250 lbs would give a displacement of 250 x 0.080 = 20 gallons, so theoretically you would need to add 80 gallons of water to get to 100 gallons total.

The data mentioned above points out that densities vary with moisture content etc, so you should take the value of 0.080 gall/lb as indicative only and experimental values will be best.

Edited September 13, 2019 by meerkat
Math was totally botched - sorry