So far I've found all the mods for the Varmint Rifle, 9mm Pistol, and Laser Rifle. Also the Grenade Rifle long barrel, and some scopes for various rifles.

Has anyone found a merchant that sells the Hunting Shotgun mods? Only found the choke tube and I'm dying to extend the ammo cap on it.

Weapon mods cycle like pretty much everything else in the merchant inventory, but the best places for mods that i have found would be Gun Runners east of Freeside or maybe better yet Alexander at Trading Post 188 which is southeast-ish of The Strip but you need a guns skill of 40+ to convice him to sell to you.

I think I saw the Long Barrel for sale once at the Gun Runner booth. Go to Freeside's East Gate then (If your standing in front of it) follow the chain-link fence on the left and you'll walk right passed it. It has a map marker to.

yeah so far the Gun Runners only sell receivers and barrel mods, gotta try sleeping for a week and see what they got.

I've noticed that the add at least misc stuff to the inventory. I go there every odd hour and get jarred powder and boxed casings and hulls. And boxes of primers.

i got some hunting shotgun MODS from gun runners, but i have yet to find a hunting shotgun.