In 22 rimfire ammo makes a huge difference in how much lead accumulates there the worst offenders are going to be anything made by Remington or Winchester ( tied for first in the how bad can we make ammo and people still be willing to buy it contest) federal is just marginally better. In domestic ammo CCI is your best bet.
If you really want to know how well the gun can shoot accuracy wise, you are almost invariably going to find higher priced ammo from Europe like Eley, RWS, Lapua and SK are going to give your best results