Most American beers tend to be weak, usually under 6% ABV (especially macrobrews, which rarely go above that and usually hover around 4%).
Drinking a 30 pack of a macro is easily doable if you don't eat anything all day, especially if you're not pairing it with liquor. An experienced drinker could literally drink American macrobrews all day long and maintain a steady buzz without getting drunk. For me, personally, I can't get drunk off of beer alone unless it's above 8-10% ABV. I do 2-4 shots and chase them with 2-3 beers tops. Liquor is just so much stronger here than beer that I don't need more than that.