Where to find hunting rifle mods in fallout new Vegas

You can find Hunting Rifle mods with numerous traders and gun shops generally, they might not have the parts at first but their stock usually changes every now and then and eventually one of the traders will have the parts you need for a reasonable price. I haven't come across mod parts in the wild, but some caverns and abandoned buildings may contain some, they usually contain some good things anyways so they'd be worth checking out if you're a high enough level to deal with whatever creatures occupy them.