I found that Winchester primers did not seat as tight in my 300 wsm Norma cartridges as CCI and Federal. Much like you, I have a pin hole in my bolt face. I was using Hodgdon Superformance loaded up near the top of the recommended range, but there were no other signs of over pressure.
FYI...If you separate the action from the stock, Beretta stipulated to me that the reassembly torque on the two action screws is 51 - 53 inch lbs. I wouldn't 'eye-ball' them. I don't know what the torque recommendation on the trigger set is, though.
The Tikka T3 trigger is pretty good for a $650 rifle, I'd say. But if you want a better one, you might try Jardinc.com The are the only place I found that sells an aftermarket trigger for a T3. I tried a Timney - they said it would fit, but it did not. Jard sells upgrade parts for the...