Just curious, were you shooting soft-points? I shot my Lee-Enfield at an indoor range once, and was made to shoot the more expensive soft-point hunting ammo. This was because the folks at the range considered any full metal jacket ammo to be armor piercing, and there fore damaging to the backstop. From what I have seen, the FMJ rounds for .303 British are pretty far from armor piercing. This policy was probably a better-safe-than-sorry attitude with a little "hey, might as well get an ammo sale out of this" mixed in.
It's weird to see the .303 British prices. There was a time when it was a much more popular cartridge, and went pretty cheap. Of course, most all ammo was pretty cheap not too long ago...
"Democracy is two wolves and a lamb voting on what to have for lunch. Liberty is a well-armed lamb contesting the vote!"
--commonly misattributed to, and most likely not, Benjamin Franklin