>>381133792
I'm guessing it's an 8 bit value with 7 bits used to represent up to 127 and one bit to flag it as timed out (999 ms). The ping in game only goes up to 255, but after that the values seem to become random, rather than restarting from zero. 

The netcode probably becomes so bad once the ping has exceeded 255 ms because the prediction actually uses the wrong values; it only interpolates your position for 30 ms or whatever instead of the hundreds of milliseconds it should thus having the positions completely desynced and allowing the shots around corners.