About the only way that could happen is if you loaded a 20 gauge shell in a 12 gauge chamber....

unfortunately that wasn't the case....there were 2 other witnesses

Never had a problem with my 870 but I short stroke my benelli nova some. I guess I am not use to a big gun.

Been shooting a Mossberg 930 Waterfowl model (not the duck commander version) for about 5 years now and its been flawless. Only time I've had any issues is if the gun gets soaked in water and not cleaned before the next trip, it doesn't cycle reliably. Don't really think that's a fault of the gun though. The only negative I can see is you don't get the same coolness points as if you had a "B" gun.

Well I got to fire 7 or 8 rounds through it yesterday. Twice I went to pull the trigger and "Click"! It appeared the gun did not fully seat the shell. Not sure if it was because the gun was new? I will give it a good cleaning and maybe I can re-try it this weekend. By the way, the hunting was a bust. One coot and two ringnecks. I think they flew farther south! Anyway, I have never owned an automatic before, so I thought this one would be a good mid range shotgun to start with.

Hope it works out for you but that "Mossberg Click" has got to be a very common problem. I bought one in 1990, had so many problems with it as others did, you would think they would have made them better by now but apparently not.
Works 90% of the time, it's the other 10% that will piss you off.

Could be you got some really, really crappy 12 gauge ammo then I guess. There is no possible way I can think of you can fully chamber a loaded round in an 870 on top of a jammed empty hull short of catastrophic ammo failure of the jammed empty that somehow allowed it to shrink and move a couple inches up the bore. There is just not space for it to happen.

Shotguns jam, it happens. It is pretty hard not to notice when it does on a pump. You don't hear the hollow sound of the hull eject, the action doesn't close(which feels and sounds different than when it does) and therefore the forearm doesn't slide all the way up like it should. There should have been some "somethings not right" alarms in your head before you tried to pull the trigger again.

May be time to slow down and pay attention next time instead of blaming it on the gun.

did you clean the factory grease off of it and wipe it down good?

before you shot it I mean

I am going to guess, not.

My 870 was doing the same thing - a couple fixes I found online were to replace the extractor - http://www.rem870.com/2012/10/16/remington-870-non-mim-machined-extractor/ and polish the bore - https://www.youtube.com/watch?v=JaeYvXRt4WE

No, it went straight from the box to the blind. Do u think that may have caused it?

Iv always cleaned every gun I get when I buy it other than the inside of the barrel for a few rounds. I don't know if all brands put factory grease on them but I would think so to keep from rust while on the shelf. Also theres no telling how long and what kind of conditions it sat out in and how well it was kept until the time of purchase so always a good idea

That can most definitely be the problem. When the guns are built and shipped they put a preservative on them that is kind of greasy and sticky, it is called something but I do not remember the name.
When you buy a new gun the entire gun needs to be taken apart and cleaned very good then oiled lightly. Without doing this you will more than likely have problems eventually cycling shells.

I have been shooting a 935 for 4 years now with no issues at all. The gun was on clearance for less than $400.00 when I bought it and it was money well spent. JMO, but it works for me.