While lots of people are free to offer up ideas, not everything can be implemented in a large scale operation. Like use of flat rate boxes....most in places have weights for products and not dimensional on every thing like bags of brass from Win etc. unlike a fixed dimension of say a box of berger bullets. Like 2 of their large boxes fit a small flat rate box, and 6 of the small and medium in small flat rate box. As related before if the shipper uses Regional Flat Rate boxes then
Things to consider using UPS.....have stuff shipped to a commercial address such as your work if it will not violate company polices. This will save you about $3.50 or more over shipping residence. Do not lie as UPS will upcharge the sender if it is not a commercial address. Rural address really bite when using UPS, might want to consider using USPS for sure in that case unless haz mat stuff.
USPS does do not pick up twice a day from shippers, unless they pay a fee for the second pick up of about $15.00.
For those in the upper midwest Speedy Delivery Service is an option that some vendors use, and their freight charges are better then most if that is an option. They Do Haz Mat stuff, so might be an option.
They will here in Louisville, and do it at many businesses! No extra charge. At some of the businesses they leave a trailer, just like UPS.