500 vs 500A

[Maser]

I can't believe that after all this time i've owned my Mossberg, I been calling it a 500 and it's a 500A. Is there any real difference between the 2 models? All the assecories I own for it all are for a 500 and they fit perfectly.

 

[One of Many]

The letter after the number 500 is indicative of the gage of the shell it uses. A is for 12 gage, and C is for 20 gage.