Exactly. If you are not making arrangements for the seller to send a gun, site unseen, to an unbiased gunsmith for evaluation before buying then you are taking your chances.
The problem with that suggestion: Getting the seller to send the gun anywhere prior to receipt of funds. Whether it comes to you or goes to a gunsmith, the standard remains a 3 day no questions asked return period. But the buyer ends up paying shipping both ways--unless the seller owns up to a very basic error (like wrong gauge), bites the bullet, and refunds your money including shipping costs.
