It's sad that so many of us rate rifles on "How cheap is the ammo?" If all one wants is the limited satisfaction of shooting surplus ammunition (and I know that many do), then the availability of such ammunition is a factor.
By allowing the presence or absence of surplus ammo to dictate our rifle choices, we could lose out on owning many rifle types which would otherwise give great enjoyment and recreation.
At today's prices for DECENT surplus ammo, it would be easy to set up a hand-loading outfit for the cost of a limited amount of surplus stuff.
I have several .303s here which have never fired a factory round since they came into my hands. Most of their shooting these days involves cast bullets. The cost-per-round can be very low, and the rounds are FAR better than anything on the surplus market.
The #4 Rifles are superb instruments. They are fast-handling, fast-firing (with practice) and effective, as already mentioned, for almost any North American game. I might draw the line at bison, with which I have extensive experience, but moose? Bear? Deer? Not a problem, given a good bullet. I chronographed some commercial Canadian 180-grain .303 British ammo some years back. It ran at 2560 fps average....compare that to commercial .30-06 180s, and you just might be surprised!
My first service rifle was a Long Branch #4 (#85L7408) issued to me in '58. Reward offered, if anyone sees it.