Awhile back the bigger scam was a forged cashiers check made out to the buyer, but endorsed to the seller, for more money than the purchase price. The seller was to send the gun along with cash above the purchase price. The buyer and his buddies must have had a good time laughing at the poor sucker who complied with the scheme. One commonly ignored detail about bank (cashier's) checks is that they are subject to a stop payment order by the originator of the check. While not exactly a "purchase/sale" here's how an otherwise model citizen, minister and Vietnam vet, got sucked into cashing a forged Nigerian bank check and became complicit in a Nigerian email scam and paid the price:
https://www.newyorker.com/magazine/2006/05/15/the-perfect-markGil
