You may need to provide some more information, and/or a photo of the trigger in question. I believe that Midland produced several types of actions, some of which were more or less copies of the 1898 mauser, others which looked similar to a mauser but used 1903 Springfield bolts.
It has been many years since I saw a Midland. I don't think I ever adjusted a trigger on one...I don't remember what they look like... I just mounted scopes and pads on them...
Any gunsmith should be able to look at it and tell you fairly quickly what can or can not be done.
