SP20 RRS occasionally just going click

So,

I have a Hammerli SP20 RRS that I have been shooting for some time and It has been running flawlessly until recently.

It will cycle and pick up the next round and chamber it. When the trigger is pressed it makes a clicking sound and the round shows a very light hit. It will do this about  2 or 3 rounds in a 90 round match. I am trying to avoid an escalation of this 

So:
I have checked the mags and it is not specific to a mag.
It does not seem to be ammo related and occurs across different ammo and boxes. It rarely occurs with SK STD+
It occurs with a clean or dirty chamber but more often with a dirty chamber. The chamber is tight and will after cleaning not eject a round until a few shots are fired and hand ejected or a drop of oil placed on the first round. 
I have checked the trigger over travel screw and there is plenty of overtravel available for hammer reset.
I have checked all the trigger group settings with the manual procedures and they are within factory spec and at factory initial settings. 
The trigger weight is at ~1027 grams 

It seems that the round is not chambering completely or the hammer is not releasing with its full force.

Has anyone seen this and what did you do to fix it?

Any help would be greatly appreciated.

I am not familiar with the SP20 , but would look very closely at the firing pin and ejector. how old is the gun/how many rounds through it ?

Check for crud on the bolt face and where the barrel meet up. Crud under the extractor or built up in the extractor spring. I shoot one of the first run SP20's in 32. It has a rubber C-clip that goes half way around the bolt. I'm not sure if that rubber C-clip is on the 22 or the RSS models.