Hatsan O-rings

Got most of them form the O-ring store but now I have codes for the following

324- air charge fixture o-ring 80-00-324
326. cylinder blind cap o-ring 80-03-326
616. mag o -ring 80-02-616

These are the numbers from the Hatsan Parts list

Why all the codes.WHY can't they just give you the size o-ring you need instead of using all these codes. This Hatsan I have I wanted to have a complete set of o-rings, maybe I will never need them, but I need more info then this to place my order at the o-ring store

I am sure others had this problem
 
Thanks i did get a bunch off the exploded view but these 3 o-rings have no measurements,, just a code number. I had problems ordering through the o=ring store but they were very polite and did the cross reference for me so I could add them to the cart. Just these last couple have no measurements to them. I probably never use them any ways but nice to have full sets for each rifle on hand. I need to find some guys who shoot air guns around where I live. I am like a sponge right now and trying to take loads of info in and lots of it is filed .bookmarked or printed out.. Thanks for reaching out