That's an important factor I haven't had the time to asses yet. Taking potshots at 10' is one thing. Firing various weight pellets at different ranges from different muzzle velocities works out to a lot of shots and a lot of time needing a decent range to test at.
-5 pellet weights: 0.2g, 0.25g, 0.28g, 0.36g, 0.43g
-4 different muzzle energies: 1j, 1.5j, 2j, 4j
-5 different ranges: 10', 25', 50', 100', 200'
-missing the chrony's target area at each range for each distance: 2, 4, 10, 20, 50 (estimated shots required to get one velocity reading at given range)
Works out to 1720 shots. Not including setup at various ranges that's almost 5 hours at 10sec/shot including reloading and fps recording.
I think it may be possible to determine safe impact energy by picking a baseline muzzle velocity that we're already accepting with 0.2g pellets. Take a sample ASG firing at the max acceptable muzzle velocity (highest velocity we're willing to accept a point blank shot) and hit a piece of styrofoam. Blue foam manufactured for insulation may be a good one because it's avail in quantity and probably is made in high consistency. Measure the penetration depth and we can use the resultant penetration depth to determine how heavier pellets behave at various velocities. Ideally, we'd make some ballistic jello, but I think that may be a lot more trouble than foam.
I think we can make a start with limited tests. I took a first stab at the issue with trying to address mercy ranges. Working out the actual safety issues with high powered ASGs and longer ranges is a much more complicated problem. I'd like to get to it someday, but setting aside a couple days to set up rifles, find a range, and find help is outside of my abilities for awhile.
Sha Do: take some potshots at a protected chrony (put some polycarb to protect the screen) at 100' and see how your rifles do with different weights of ammo. I would also be interested to see how airsoft players perceive ranges. Measure out some targets at random ranges and ask players to estimate how far various targets are. Have them write down their estimate for say 5 targets and see how well they perceive range.
Want nearly free GBB gas?