SKS Question

[RossA]

I have looked all over and haven't found the answer to a simple question.
I have a Yugo SKS with the grenade launcher. There is a "switch" or button which allows you to go from semi auto mode to grenade launcher mode.
Which way is which? Down for semi or up for semi?
Haven't shot the rifle yet, and I assume that one shot will tell me if the rifle is functioning semi, but it would be nice to know.
Thanks.

 

[Limeyfellow]

Down to the right is semi automatic. Straight up is in the grenade firing mode and will disable the gas from reaching the piston to rechamber the rifle.

 

[RossA]

Excellent! Thanks.

 

[Bentonville]

Just for fun go to http://www.sksboards.com/smf/index.php and read up on lots of SKS stuff.