Suggest that they carefully polish up the face of the Trigger / sear so that the two surfaces are parrallel, corners are sharp and the trigger breaks cleanly when a certain pressure - say 3lbs is applied. If the two surfaces are rough then the trigger pull will be roguh, draggy and inconsistent.
The trigger will also be adjusted for over travel and weight.
Be very cautious of any trigger that has been "adjusted".
But the following are simple tests that should be done reasonably regularly.
With an UNLOADED rifle
1) vigourously close the bolt (you have a charging buffalo running at you type speed and vigour) - check that the firing pin has not fallen. If it does then likely the rifle will fire when you chamber a round.
2) close the bolt - safety off.
Thump the rifle with your hand, jar it indeed thump the rifle butt on the ground
3) Safety ON - repeat the above.
4) Safety ON - repeat the above and then release the safety.
If the firing pin falls in any of the above tests - Do NOT use until it has been looked at by somebody who knows what they are doing.