Jam the gun

Don't know why after a thousand shots, my new VSR-10 (MP001) rifle with no more BB coming out. Followed instruction to maintain the gun with a piece of cloth inserting the barrel to clean and lubricate the cylinder wall with silicon gel, the gun functions again. But it seems nothing much did I do on such simple maintenance, the gun returns to normal condition. How come?

You might get a piece of dirt or there is enough friction in the barrel that without the cleaning and lubrication the bb gets stuck and can't fire.

I have experienced this with the same gun, but it was not shooting because the magazine wasn't feeding, because the little piece of plastic that holds the magazine in was not clicking into the right place. I think I fixed this by luck, I was angry and I was pushing the piece back and forth hard while pressing the mag release button and somehow I fixed it.

The magazine latch is the weak point and bad design. I experience the same after 1st hundred shoots. Normally I remove the magazine, clear a BB out from the chamber, empty fire once, put the magazine back. The gun is resumed.
Every time I check the push button if it comes out properly after the magazine is inserted to make sure it fits properly.