I had a similar problem today repeatedly with my MOdel 12 BVSS in .243. Even when pulling straight back, if I squeezed nice and slow, the accublade would not allow the shot to go off. It was as if I were pulling the trigger without pulling back the accublade, although it was pulled straight all the way back. "Clunk" and no firing pin. Does anyone know if the accublade is adjustable?? The rifle would shoot fine if I pulled the trigger fast, but slowly squeezing it the right way seems to make it go off in safe mode as if the accublade were still engaged. My model 12 in 22-250 funcitions great.
Any insight will be appreciated
Best regards
Fred
Try adjusting your trigger pull a little bit to see if it goes away. I had the same problem and stiffened the trigger up just a tad and it fixed it.