I'm not sure what you mean by availability? If you are hunting and go to the only store in a town of 2000 people you will find 30-06 and 30-30 on the shelf with the 12 ga and .22. If you are talking surplus ammo the .308 is more available, but the 30-06 can still be had. For those that reload, the 30-06 goes from 110gr to 220gr which is hard for the .308 to do on the upper range. For hunting rifles my opinion is the 30-06 has the largest number of models from the various manufacturers, but that doesn't mean much since the .308 is well represented. There can't be a quarter pound difference in the rifle weight. MWT