Thanks for bringing this forward. Anytime a trigger has been removed, adjusted or worked on, it should be tested and inspected prior to inserting rounds. Thank god no one was killed or injured.

Unloaded check for trigger and sear contact. There should be enough preload to keep the trigger pressed against the sear where gravity or bumping will not lift it off of the trigger shelf. Check for safety function. Safety should slide into all three positions when cocked. Trigger should not be able to be fired in any of the two safety positions and only fire when the safety is in the fire position. This includes bump testing.

This is a perfect example of the responsibility more experienced posters have, and why we should discourage fledgling DIY'ers from working on triggers without some clear cut parameters with precautions and testing explained like the above paragraph inserted into any discussion with regards to triggers and there modifications and adjustments.