I'm not saying his own LS wasn't carrying it, or that his striking strength is massively inferior to it.
Yeah, that's why I'm saying that a simple Gum-Gum Pistol from Luffy shouldn't be fully scaling to the Gold Rifle either.
Okay, not "feel weird", but "I don't see a good reason for Luffy's most basic attacks (which 2-shot Usopp) to scale to Luffy's best shown attack, which at this point is the Gold Rifle."
I'm aware I may be in the minority on this from a powerscaling standpoint, but even though Luffy was fighting Usopp "seriously" during their duel, I don't think his moves scale to the Gold Rifle punch.
I think it would be better if Usopp was downscaling to baseline City level to be honest considering how quickly he was taken down, and the other factors which made the Gold Rifle more powerful than Luffy's simpler attacks.