on my clan server i have it at 5 cause when we are practecing we really should not be shooting each other ,

i think 50 is a bit high even for a public one, cause taking 50 off per minuit, however im not sure what it takes it off of,
im not sure if its 50% or 50 damage either way its either 2 mins or 4min respectivly i find if there tk goes quite high and does not drop at a high rate they will actualy play alot more carefully which helps us all

for public i would say 15-25 is resnable, or mabey im just not forgiving enought  

Just one thing...it has nothing to do with PB. This is a game feature that was added in the patch.