With ammo scrounging 1, cha 3, and focusing on semi auto pistols, and rifles, 10mm, .38, and .45, I have more ammo than I could ever use. I've purchased ammo maybe twice just because i needed value for the items i was turning in for caps. I started the game normal and had to turn it up to very hard once I was in the 20's and unlocked gun nut/armorsmith 3. Combat style is just semi auto supression fire, and switching to combat shotgun and blasting them in the head when they close in and round corners.
Even with no +dmg% perk the crank lazer rifles are extremely powerful for conserving ammunition since it seems to punch through enemies DR. Also frag grenade/mine kiting the bullet sponges helps a bit too.