What the title says. Everywhere i go including the gun runners they only have some weapon mods and they are oes i either dont, dont need or already have. So is there a shop that specialises in or has alot of weapon mods?

The closest you'll get is the guy at the 188 Trading Post I believe...

And that's only if you have the required Guns skill.

Vendor stock changes every 72 in-game hours, so try waiting and see what happens. That said, the random-spawn nature of the weapon mods and other types of items really pisses me off. I have the gun and the caps, but I'm not allowed to buy the item just because I didn't show up at the right time? Screw that. If they wanted to make it difficult to obtain mods, they should have put them in unique locations or just upped the prices.

He is a Gun Runner. But Gloria Van Graff sells Energy Weapon Mods, not much I believe.