I used to find my AA400 used to go to pieces if I cleaned the barrel.
Completely opposite to my HW100 which I would have to clean the barrel every other week otherwise it would not group well at all.
With my Daystate I would clean the barrel every time I started a new tin of pellets so every 500 pellets.
This always worked for me

I only ever used the small felt shoot through pellets usually 3 or 4 until they came out of the barrel clean.
I was always told rightly or wrongly years ago when I started shooting never put anything harder than a lead pellet down a rifled barrel.