Ok so I got bored over the week end I skipped out on doing any of the honey do list so I decided to make up some arrows and go test them.
I done this because of all the FOC, KE, andSPEED threads that have been popping up lately.
Now as every one knows I am a Extreme High FOC guy and all my arrows have FOC above 20%.
What I done was get an arrow to weigh as close as I could to 300gras the test bow is my Marquis 60lb 28" draw.
The first arrow is 302gr with a FOC of 6%
The second arrow is 480gr with a 24% FOC.
Both arrows where spined perfectly for the bow.
I first shot the heavy arrow through the crono at point blank 249fps KE 66 ft/lb
Then the light arrow 299fps KE 59.9 ft/lb
Ok now for the fun.
Heavy arrow
10 yds 245 fps KE 64.1 ft/lb
20 yds 241 fps KE 62.3 ft/lb
30 yds 238 fps KE 60.5ft/lb
40 yds235 fpsKE 58.8 ft/lb
50yds231 fps KE 57.1 ft/lb
After a couple of minor tuningadjustments and resighting in for the light arrow.
10 yds 292 fps KE 57.2 ft/lb
20 yds 285 fps KE 54.6 ft/lb
30 yds 278 fps KE 52.1 ft/lb
40 yds272 fps KE 49.7 ft/lb
50 yds266 fps KE 47.4 ft/lb
So doing the Math the heavy arrow lost 18 fps and 9 ft/lb of Ke and the light arrow lost 33 fps and 12.5 ft/lb of KE from 0 to 50 yds.
Rough guess is I will be sticking to my Extreme High FOC moderate heavy arrows
Dissclaimer:
No Cronographs where killed or injured doing these tests
Week End testing
just put up a new privacy fence, replace the back door and build a new shed you know just the normal week end stuff to do 
