I find 10' an awkward range in a CQB setting to begin with especially at TTAC3 where typical engagement range is often very short with many kills made just as one rounds a corner.
That being said, I also think 350fps is high given the typical engagement range. Other than affording the convenience of allowing some outdoor fielded guns at TTAC, I see little contribution by having such a high muzzle velocity. Stock gun velocity is difficult to dodge at typical CQB range so the added pain and potential lost teeth doesn't seem to be worth very much. Ditching a mercy rule with lower fps limits would go towards reducing injury and improve the game with no expectations of mercy.
I could even see a use for particularly low powered airsoft (say stock guns or MP7's) being allowed to fire full auto. The stock MP7 only puts out a piddly 215-220fps. Perhaps allowing low power airsoft to be played full auto in tight CQB could add to TTAC3 games.
Brian has been running TTAC3 allowing 350fps for some time now. Considering the typically close engagement distances and relatively high max fps allowances, there seems to be very few complaints of undue pain from particapants there. We have probably been overstating the safety requirement for a 10' mercy range.
Either that or we have been understating the acceptable minimum mercy range as 10' provides little impact reduction.
Want nearly free GBB gas?