I would not rod an airgun barrel. It is not necessary.

Was the brush bristle or wire. Both are not good news IMHO.

Get a pull thru and some .22 patches......some good quality gun oil and pull through till they come out clear. Then a few dry ones.

A clean barrel can actually open a group until it leads up..... or it can tighten it. Each barrel os different.

The pellets are buggered.