[massnee]

I have a mossberg 500. I have noticed that the shell to be chambered will fall out if the shotgun is shaken or turned on an angle.

Is this normal?

[mnrivrat]

The short answer is yes - it would be normal for the shell that is released onto the lifter to be free enough at some point in the stroke to roll out of the ejection port, if you tilt the gun and shake it.

[bensdad]

More information is needed. Post pics or a more detailed description of what you mean. The answer to your question is no, this is not normal.

ETA: Yeah, good point. If you're doing a half-stroke, the round will roll out if you tip the gun. Don't do that.

[Virginian]

It is perfectly normal. I have never seen a shotgun with a bolt action Mauser style controlled round feeding system. After the magazine releases the round, and before the lifter and bolt carry it into the chamber, what's to keep it from not falling out? It's just like driopping a shell into the open port.
Note, bottom loaders like the BPS, Ithaca, etc., are different and can not "lose" shells at this same point in the cycle.
It is such a non big deal, that the military and police don't worry about it.