Answer

Check to see if the Sear Spring is broken or something is just not right with it, Check the Sear to Hammer, is Positive. Check; make sure there is nothing in the way of the Trigger and Sear. Sometime there maybe brass from the Round blocking things in the gun. Were the Rounds feed up. Check the firing Pin Hole make sure it is not sharp. TC

Answer

Check the disconnector too. It could that when the trigger is fully pulled back, the trigger couldn’t disconnect from the sear. TL

Follow-up on question

The sear spring is OK and when cocked it has no push off. The sear is rounded and does not have a flat single facet like a conventional sear, the hammer notch looks conventional but is slightly rounded at the lower edge. Is this the way that the sear is designed or should it be shaped more conventional with a single flat facet? Hard to tell if it is made this way or badly worn. If not correct this maybe part of the problem but I do not think it is all of it. If not right this needs to be fixed but I would like to know that it is not designed this way before I start cutting and ruin a good part. When the trigger is pulled hard the sear rotates in it’s arc until the sear disengages the hammer and the hammer falls, the sear drops off of the front edge of the disconnector and rest on the front of the disconnector and as the bolt cycles and cocks the hammer it catches the hammer in the notch and tries to hold it but it just barely slips off(only when trigger is held fully to the rear, if you let off of the trigger even slightly it will catch and hold the hammer cocked). I think the sear and disconnector may need fitting to allow the sear to drop down more when it falls off of the top of the disconnector and allow the other end of the sear to engage the hammer deeper when the trigger is fully pulled, so that it will hold. I think this is what I will try if the sear and hammer does not need re-cutting.