Open player.cpp and look for gmsgAmmoX definition
we need to change that 2 to -1
then look for the function SendAmmoUpdate
we need to edit those WRITE_BYTE from the message and change them to WRITE_SHORT, also change the 254 to 999(the new ammo limit, now just limited by the HUD)
then we need to open ammo.cpp and go to the ammox function
we need to change the READ_BYTE to READ_SHORT
with that now the client receives the information of the ammo, up to 65,535 theorically but you need to modified the HUD in order to expand the digits shown.