Possible. That MIGHT change the head space from what it was formerly but it would have to be a significantly different locking position than the factory stock. Look at the factory stock and see if the closed bolt handle was resting on the wood or the receiver. You should be able to see wear marks or oil stains if the bolt handle was against the wood when fired. If it appears the bolt handle was free from the wood and only locked against the receiver, I would carve out the bolt handle channel on new stock till bolt handle is again free from it and resting on receiver when bolt is locked.
I think this is a bedding issue. Something is flexing that shouldn't be when the gun is fired. Make sure the barrel is free floating and bed the action both fore and aft with JB Weld. Lots of videos on the net to help with this. I have used spray on silicon as the nonstick agent. Works well for me and not as messy as some of the other stuff used in videos (e.g. boot grease).