Bobt
The accepted procedure is you meet with the buyer. He pays you (or partial payment), you issue him a dated receipt, signed by him and you with each persons FOID info on it.
The clock starts here. He wait exactly three days (yes, right to the hour) and returns to pick it up then. You note on both copies of the receipt the date and time the pick-up was done and both initial the pick-up information.
You are now in compliance with the law.
The "spirit" of the law was intended to restrict someone from rushing out after a heated argument (for instance), buying a gun then shooting the person they had been arguing with (or the newly discovered wifes boyfriend)
. It was intended to allow someone to "cool off" and begin rationally thinking again.
As SG-688 said, there are many instances on record where a seemingly "safe " sale was made and then a horrific event took place shortly after.
The money order does you no good since you have not documented the original purchase with the FOID info and signatures and therefore the waiting period cannot begin.
Over a forum or mailed money order situation and without meeting the buyer, you have no idea who the buyer is or who is actually picking it up. May not be the same person and that constitutes a "straw purchase" (one person buying a firearm for another that may not meet the ownership requirements i.e. no FOID, convicted Felon, etc).
Perfect example is you buy a gun from an out of sate dealer. It is then shipped to your in state dealer for transfer. When it arrives, you meet your in state dealer, complete the paperwork and WAIT 3 DAYS, even though you paid the out of state dealer up front probably over a week or so ago before shipping. Same rules apply on the waiting period issue with a dealer sale or private sales.
Better for you to be in compliance...and now you know how.