I have done dozens, if not hundreds, of transactions with USPS MO or personal checks with no issues. I live in a small town, with the Post Office about 5 minutes away. My bank and PO are within sight of each other and there are virtually never more than one or two people waiting in line at either.
I have a PayPal account, but seldom use it and never for firearms. I have made it for 70 years living like this and sure as hell won't be changing any time soon.
donsm70