The gun was a cheap Daisy break barrel springer made in Spain. I bought it around 20 years ago and it never shot well at all. In fact it shot poorly.
Around once a year I would take it out and hope it had somehow changed but it would always be the same old storyl Bad accuracy.
Pellet barrels are not supposed to need a lot of cleaning and sometimes none at all but I finally got out a jar of Hoppes #9 and began cleaning the bore. The problem was the patches kept coming out black no matter how many I put through it.
I finally took a bronze bore brush to it and that did it. The first three patches came out filthy but by the fourth was nearly clean. I then pushed a couple through with Mil-tec1 to prevent corrosion and then wiped it with a dry patch.
As soon as I started shooting, it clearly had become a different gun. I think that one group was one of the very first. Interestingly the rifle was made in Spain and the cheap Daisy pellets were also made in Spain.
I never did get any groups that good again but just about all of them were close to that good.
My Grandson has it now.
Helluva Good Job !