I'm going to do my best to describe this issue, i have looked everywhere for an answer but no luck yet. So i come to you guys for help. I recently attempted to do a trigger job on my full size m&p 9mm. Being my first time doing anything like this i did not want to attempt to file anything down so i just stuck with polishing. After i finished put all back together I began to function test everything and the trigger was not breaking even when i pulled it all the way back it would not break but after pulling it multiple times one out of every 15 pulls it would break but only if it was fully pulled to the back with a lot of force. So I field stripped it to check the trigger bar and sear which operate flawlessly and the striker is good as well. Then i discovered that the trigger works flawlessly with the rear roll pin not in even if i put a punch in and apply pressure down it wont fire but no pressure it works flawlessly. sorry for the long post but i figured i would give all the details.
Hope someone can offer me some advice, thanks in advance