The Hatsan Gladius Cocking Issue problems

In this video I try to sort out my Hatsan Gladius that does not always engage the cocking mechanism when shooting. It involves removing the stock and adjusting the three adjustment screws. I can get it to work for so long, then it will go back to not cocking again. The trigger sear is probably worn, but unless I can sort the problem out, it has become quite a pain in the bum. I will have to fully strip the rifle down I think, and check to see if the parts are warn. Tollerences are quite high to get his rifle working correctly, so its not an easy one to get right as you will see in the video. The rifle has probably had 20 thousand rounds through it since I have had it, so its not done too bad really. I will work on it and come back to you all later when I find out what needs doing to correct it.