I have a 900 that I purchased 4 years. I was injured in a work accident and never set it up. I put it together  last week and I am having a problem. It works, most of the time, at the factory settings.
When I try to reduce the shot size to 7/8 ounce the powder bar binds and pops  the bellcrank cube. It seems to be binding on rubber insert but Im not sure. If I adjust back to 1 + 1/8 it frees up. There are several other issues I will try to rectify on my own, crushed cases and unseated primers.

Thanks