[UPS and FedEx rates have] increased in the last six years, but so has the price of fuel. Not close to "three fold". Remember, UPS/FedEx don't do "Flat Rate' like USPS, their rates are dependent on weight and distance.
FWIW I recently made the mistake of using UPS to ship a C&R handgun. It wound up costing almost double
what it cost me to ship a heavier gun about the same distance 3 years ago, and although I don't have the receipt handy, IIRC I got hit with a ~$7 fuel surcharge and a ~$6 "Rural Area Delivery Fee" (or something like that).
This is the last time I ship UPS. If I sell any more C&R handguns, they will be shipped via USPS by Dogtown Tom.