on/off top question

[nipplez]

i got my gun used and when i took it apart to clean i noticed my on/off top has one wide end and one narrow end.
sorry about the crap illustration but it bascially looks like this. My question is which way should it face? Narrow side touching the on/of bottom or Wide side touching the on/off bottom?

on/off bottom
______
[ ]
[______]
_[ ]_ pic #1
[______]
on/off top


on/off bottom
_______
[ ]
[_______]
_______ pic #2
[_ _]
[ ]
on/off top