Extra Part in Mossberg 500 box
 

Hi,
Recently I bought a Mossberg 500 shotgun that is the combo, came with a field barrel and a rifled slug barrel with canilever scope mount on it. The stock is wood and there is a replaceable cheek rest on the stock.
In the box was a small manilla coin envelope that had a part in it that makes no sense.
The part looks like a bushing of sorts, approx 1" long, hollow tube with a flare on one end.

Any idea what this may be?
Thanks
T

A choke?

JD

Threaded? I vote choke tube also. Does it look like one of these?

Had to resize pic.

Sounds to me like a choke tube wrench.

Uh...edit... never mind I was thinking something else, don't ask me what.

Nope these are not the chokes. This item is much much small, I forgot to mention the diameter is probably 1/4" or less. Looks like a pin, hollow though, with a head on one end.

Cap/cover for the pistol grip screw? Sling swivel stud? Pics would help.