I forgot to ask... were the primers going off?

If not what type of depression were you getting on the primer face.... Is there any evidence that the hammer was hitting the primer.

It would be awfull tough for the gun to be so far out of tolerance that the primer would not go off... it might be dirty but the primer should go off.

Other thoughts....

Put the gun together, but remove the primer adapter...

Close the bolt and drop the hammer, either by puling the trigger as you push the bolt handle down or just pull the trigger. You should now be able to look in the bolt opening and see the hammer protuding out of the bolt. It should almost but not quite go inside the column/primer pocket of the breech plug.

The other possible promblem.... remove the hammer assembly from the bolt... Follow the firing pin back to where it attaches to a inverted cone.... this cone must drop into a simular inverted cone in the fact of the breech plug for it to extend completely. Often this cone in the BP can become caked with carbon not allowing the hammer to drop all the way...

Just searching, but the chances of it being the BP are remote, it is possible it could be the vent liner if it is not clear and open...

Like I said just reaching for thoughts....