Helping Ukraine: Sabotaging Heavy Artillery

Would it be possible to use a drone to insert small ball bearings into an howitzer canon? Would ball bearing create an obstruction to the canon shell and cause the canon to blow up? If not ball bearings, would anything else dropped into the canon barrel create a problem for firing the canon safely? And if ball bearings would roll out the other end when the canon was loaded, could the drone be designed to squirt something into the barrel first, maybe something sticky like highly expanding foam that would trap the ball bearings in the canon, creating an obstruction?