Once the money order is cashed the USPS is done with you, the buyer. If the seller doesn’t send what you paid for, you are on your own. With a personal bank check, you at least have bank looking for ID, a copy of the endorsement, potential video of the transaction at the bank counter and likely an account with a bank before the the check is cashed.
OK so a couple of things...., I wrote "offer" a USPS money order. That's a test, because it forces the seller to give you an address..., say "no" if the address is outside the USA. Forgive me for not being more precise.
Once the USPS money order is cashed, if you are ripped off, an LEO can ask the USPS to reveal where the money order was deposited. While yes a bad guy can get false ID's, fooling a bank is a bit harder than a fake ID and some cash into the hands of the doorman at the nightclub, and if he's not making a lot of money in a single score, then he's likely not very sophisticated.
IF you pay with a personal check..., and it's from your regular banking account and not an account that you've set up for such transactions, then the bad guy has your account number and bank routing number on the check that you provided. It's a simple task from that point on to drain your account pretty fast with false checks.
So there is no real way to stop all the fraud, but this guy is pretty obvious.
He is new
He has few if any posts (look on his Avatar)
He never sells, but "knows" somebody who does, and gives you the email
When you write, you get a reply with a great offer on a sale, and likely get photos from the internet
He thinks the amounts are small, so nobody will really follow up.
He uses the "friend email" as he thinks this cuts him out of any follow-up investigation.
He likely is in another country, and the PayPal money or any other service goes into one account, then launches it to another account...BUT
He seems to write good English.... better than say Google Translator, so he might be in the USA or Canada.
He is likely NOT at all able to converse about black powder, otherwise he'd have spotted that we are noticing his lack of comments, and would build up a comment count before trying a rip-off.
LD