USPS Priority is hard to beat for the flat rate boxes if you ship heavy stuff.

I think every ammo hand loader in the nation said a huge "Thank you" when USPS offered $15 for a large box up to 70 lbs. That has saved us all a good bit over the years.

Very few things can fill one of those flat rate boxes up to 70 lbs, but if you fill one up with lead you can easily get it to 70 lbs.

Nothing quite beats the look of a delivery person when they are lugging a box up to your door that is within a few ounces of 70 lbs. I am sure hand loaders are hated at every step in the delivery chain.