Mossberg 500 scope mount question

[Tom Dooley]

There are 2 scope mount bases for the 500. Weaver #88 is for models before 1997 and 417M for models after 97. I am not sure what model 500 I have but I have both bases. The 88 is taller off the receiver and has smaller screws. My 500 takes the smaller screws of the 88 but I like the 417M because it is shorter off the receiver. I put the 417M base and the 88 screws on my gun and see no reason why it will not work. Is anyone familiar with this and why have 2 different bases for the 500?

[natman]

Before 1997 the receivers were'nt drilled and tapped from the factory. After 1997 they came D&T from the factory and used the larger #8 size screws. If your receiver takes the smaller screws, I'm going to guess that it is an older model that was D&Ted after it left the factory for the smaller and more common #6 size screw.

[Tom Dooley]

Thanks for the reply. I looked at the serial # and it has 97 in it so figure it is a 97 model. Not sure whats going on with it but I got the shorter rail mounted up which is what I wanted. Thinking about buying a Weaver micro dot to go in it.