Don't most Moisin-Nagants use oddball 7.62x54R ammunition? Honestly...I want something that uses a common caliber...308, .30-06, .223, etc.Besides an AR10 or similar heavy hitter, something to consider is a Mosin-Nagant. They're relatively dirt cheap, battle proven and with a great reach. I paid $120 for mine two Christmases ago. The link has them higher, but I'm sure you could find one cheaper in good condition.I'm pretty much set up on ammo. The AR10 is on my bucket list. But I definitely will pick that up this weekend.
Ammo is cheap too: Rifle Ammo: .223, 5.56mm, .270, .308 & .30-06 Ammo
A rifle, 500 rounds of ammo and a waterproof storage container can be had for under $600.
Slightly more expensive is a Mauser 8mm or, like mine, Zastava M48: