Actually very efficient. One .50 BMG hits harder than a dozen of those
center fires and as much as a box of .22rf
The bullet is 700-800 gr with around 14,000 ft/pounds of energy that
can easily reach out 2000 yards for a lousy $4 a round.
I never shoot zombies until I can see their glassily fixed eyes.
Besides, the .357s are about 30 cents each now, and so are the .223s,
and .22LRs can be had for a nickel this week. Prices are indeed dropping.