Gunsmithing Trigger/cocking issues

[Gledeasy]

I have a Rem700 clone action with a jewell trigger. Noticed today that about 50% of the time when opening/closing the bolt that the firing pin wouldn't stay cocked. Just as if I were pulling the trigger to safely decock when closing the bolt. I haven't had this set up for very long and don't know what the trigger is set at. Could it be a dirty trigger, trigger too light, or improper timing? Thought I would ask here as I've had some minor problems here and there with this rifle. I have no desire to contact the smith any more as it's been a joke each time so any help here would be appreciated.

Thanks

 

[insight3b]

Probably the sear engagement. If the unloaded rifle is sitting in your lap muzzle facing right its the third screw from left to right. Cock the action(if you can) and turn the screw IN until the firing pin drops then back it out 1 full turn then normal tests for trigger/safety function.
ETA it is easier if the trigger guard is removed

 

[MikeEzell]

A simple re-adjust should take care of it. The weight of pull screw can work it's way back a tad too. Take the screws out and put a very minute amount of blue loctite on them when you go back together with them.