Heavy Shifting
 

I am installing a rear derailleur for the first time and throwing in some new cables/housing. I installed it and I can successfully shift to all gears and the pulleys are aligned, and there's enough tension (i think!), etc.

Shifting is quiet on some cogs yet feels 'heavy' ie there's a clunk when shifting into some other gears that is both felt and heard in the drivetrain. Is this a fault of my amateur pedaling or a fault in my servicing the rear derailleur or chain? I followed park tools and campys instructions, as well as some youtube videos but can't seem to figure out if this issue is normal or not. How can I fix this or is it normal?

What cassette range? What cogs evidence the "problem"? E.g. on an 11-32 some of the jumps between cogs are much greater than others.

It's hard to say, but I suspect it's merely that the derailleur is noisier than your old one. No harm in that, unless you're trying to make stealthy shifts in a race. ;)

it's a 13-23 cassette, campy spacing. it seems cogs 4-7 are fairly clunky, but then again maybe I'm not used to the group. I switched from a smoooooth campy 8 speed to indexed 9sp veloce.

b screw? is there even one on your derailleur? maybe you should play around with that.