Hammergun 20in Barrel Cleaning Is Working -Pic-Ammo Query

[Blue Heeler]

Thanks for the good advice. Most of the crud has disappeared. There is still some residue.I will let it soak in penetrating oil and repeat the treatment next week.
This little Rossi seems pretty well made for a relatively cheap shotgun and is nice and tight. I noticed that there is a tightening at the end of the barrel which is some form of choking I guess.
I have a query about ammo. I have several boxes of factory ammo (Champion - Made in Australia) the box says:- 12ga, 28gm, 6% Shot, muzzle velocity 1450fps, size 7 1/2. It is all I have ever used because I was given a case of it years ago. Is it OK to use in the Rossi?
I don't think I'm ready for Dragons Breath, screamers or Bird Bombs just yet.