here's what I posted in another forum:
The purpose to me, and from what I read, is to show who I bought/sold to and when I sold/bought it. I sell a firearm to a seemingly normal & rational person who might not be planning to heist a bank but they may end up having a very abnormal and irrational moment somewhere down the line (get mad at a spouse, mad at life, road rage, whatever). Should that unlikely event happen I want to be able to show that I sold that firearm legally, had no reason to believe this person was a nut, and no involvement after the date on that receipt.
I also want some kind of proof that I bought it legitimately should law enforcement ever question me about my firearm, if it's stolen while I own it, for my own records, and also for insurance purposes. It is perfectly within your right to not want to show me ID or sign anything. It's also in my right (and best interest) to not deal with buying or selling to anyone that doesn't feel they need to do that. To each his own. Going to court or being questioned by LEOs isn't always enjoyable. I'm not a lawyer in any shape, form, or fashion but I imagine not having any proof could make that even less enjoyable.
Maybe writing down the ID# is a bit much for some concerned about identity theft but if you won't even show me ID than I've got concerns. The best way to show me you're a legal resident of the State is just show me a State ID. Everything else I'll take on good faith. But I'll definitely need a receipt.
And to anyone that thinks it's silly to CYA in legal matters... I mean... really? Lawsuits and being wrongly accused seem WAY more commonplace then shoot outs in this modern day society. Someone becomes a millionaire from being dumb enough to not realize fresh coffee is hot and another person loses their job for defending their self from being killed/shot at work. If I'm willing to buy a firearm to CMA than having proof of a legitimate purchase shouldn't be too much to do.
With all that said and done in the end = To Each His Own. I just wanted to share something I thought would help those interested. That's my buck fifty anyway.