I have a separate insurance policy for shipping, has a $1k deductible so I only insure with the carrier for $1k and I am required to have a adult signature. It will not cover any loss if I use USPS, I must use FedEx or UPS. Sent 2 guns this week worth $50K from PA to TX with FedEx for $30.
For most long guns I am using FedEx, the exception is guns going to AK & HI then I use USPS & pay for the insurance.
Handguns generally go USPS Priority to a dealer & I pay the USPS insurance.
If you have to file a claim, UPS has been by far the worst (It has been awful!), USPS not as bad, FedEx was much better/easier. Thankfully I have very infrequent claims.
USPS tracking does suck although it has gotten a little better in the last few years. Had a slow delivery to a remote location in CA, one email & phone conversation with my FedEx sales rep and had everyone at the CA location straightened out & running to make the delivery...try that with USPS.