As i have already said your ping Determines how far infront u have to aim so a pistol with 0 ping aim straight at there head at even the Pistols max range at it wil lhit em there
GO into a server and u have say 124 ping u will have to aim that pistol about 1 CenterMetre ahead (about 1 rd of a inch), now say u joi na server where your ping is over 300 with that pistol u will have to aim a Inch or more infront to hit them