Today I went out and shot 250 rounds of Federal American Eagle 180 grain through my H&K USP 40 compact with factory mags. About halfway through I would fire and when I would release the trigger for it to reset it would get stuck and I would have to barely touch it for it to reset all the way. The gun is kept very clean and cleaned after every shoot. I didn't have any problems as far as firing though because every time I wanted it to go bang it did. I got it field stripped and didn't see anything out of the ordinary. I cleaned it and lubed it up real good especially the lower half and after that it went away and I had no more of the "trigger stick." Anybody have any ideas on what could have caused this?