I have been shooting the steyr m 40 for a while now, I got it used and the trigger is OK. I recently acquired a NIB M9-A1 and the trigger is gritty and heavy(compared to my other pistols) I have been studying the pistol and how it works and today I totally dis assembled the sub frame assembly and I was able to lighten the triggerto about 3.5 lbs of pull. So here are some explanation on how this pistol works. The whole firing sytem is an engineering marvel based on a type of sear called " falling block system" with a few modifications for incorporation of safety system. The firing pin catch(#10) rides on a pair of slot cut out on the sub frame(#6) and the lever(#11)is on a fixed pivot on the sub frame. The front end of the firing pin catch(10) rides on the top edge of the lever(11) during the cocked position in which the firing pin spring(46) pushes the firing pin catch and the lever forward. The striker(43) at this time is partially cocked.(The nub of the striker and the nub of the firing pin catch block are in contact at this point). When the trigger is pulled to fire, the trigger bar(16) transfers the movement to the firing pin catch(10) by pushing on a slot cut underneath the firing pin catch(10). This moves the firing pin catch(10), the lever(11) and the firing pinr(43) backward compressing the firing pin spring(46) towards full compression. The firing pin catch(10) continues to move rearward while the lever is stopped by the firing pin catch pi(14). The front end of the firing pin catch(10) disengages from the lever(11) causing the front end of the firing pin catch(10) to fall down, releasing the firing pin(43) and firing a round. The respective springs acting on each part mentioned returns everything to rest position(uncocked). To improve the trigger feel and the pull of the trigger, I polished the top of the lever(11), front part of the firing pin catch(10) and the top part of the firing pin to reduce the grittiness. I did not attempt to lessen any spring tension because the system runs on the correct balance of the springs. I also polished the insides of the slots for the firing pin catch and the contact surfaces for the trigger bar. Another thing that might reduce the trigger pull is if you can make the angles of the firing pin nub and the firing pin catch nub(I better leave this alone) or maybe reduce the firing pin spring tension. Just polishing the mentioned areas gave me a smotther and better trigger pull. I hope this helps anybody with this type of pistol.