O.K. I have this chain H30 072G 325 .050"/1.3mm I understand the 072 # chain links 325 ? .050 is the size of the groove in the bar. So what is H30 ? How can I have two chains 325/.050/072 one has H23??? 325/.050/072 one has H30 Can I run them both on my 350 with the 18" bar? I would like to understand so when I go get a full chisel RS or a LPX from an Oregon dealer I will have a clue!! This crapp is getting to much need much beer!