High Standard Help

Recently inherited a High Std. 104 Military.  Trigger is absolutely frozen solid, gun is actually in good shape except for trigger area which is rusty. I am soaking.   Also, adjustment screw in back of receiver is un- screwed. I am not familiar with the setting or adjustment, any help will be greatly appreciated.  
Thanks in advance   Jim

If it is a single screw its the trigger pull screw. Screwing it in increases the pressure. Minimum setting is the screw flush to the receiver..

Call Interarms about your HS, Alan can talk you thru it