What is "Gunzilla" pray tell? That is a new one on me.Get a jug of Gunzilla , soak the bore over night wetting it with a cloth patch and the next day push a tight patch on a jag through the bore. It will lift lead out of a bore better than anything I have used in the last 50 years. A tight patch will squeal like a little pig as the cloth snags the Gunzilla de-solved lead and carbon deposits.
Bunk