I still think it is primarily supply and demand with the emphasis on supply. If supply of a product is limited, and the demand is static or increasing, the price will rise. Everybody produces tons of 30-30, .243, .270, .308, 30-06 and even 7mm Mag ammo. That is why the prices on those guys are low (or at least reasonable to a buyer). The manufacturers make a lot less 25-06, .260 Rem and 7mm-08, so the prices are higher for those cartridges. That also helps explain why .223 ammo is so cheap compared to other centerfire cartridges, there is a TON of it being manufactured due to very high demand. Prices on .250 Savage, 257 Roberts, 6mm Remington, 6.5x55, 7x57 and .280 Remington are even higher than the 25-06, .260 and 7-08 due to their even more limited supply (and demand). The short magnums and other more obscure magnum cartridges do have some higher costs associated with them (case size and construction, amount of powder needed, more expensive bullets), but they also have much more limited supply due to limited demand. The best option is to load your own. Powder, bullets and primers are universal in terms of cost and utility. The only major increase in cost will be for brass, based again on that supply/demand rule. So when you find a good deal on costly brass, load up!