Make sure your Mil-Spec hammer has a true USGI profile at the very top. Like an ALG hammer.
Sometimes, the ramp portion on a 9MM PCC carrier can be to long, and the tip of the hammer profile, does not allow full cocking of the hammer with anything less then a USGI hammer profile.
If the ramped area on the carrier bottom is to long, the hammer sometimes isn't allowed enough depression to fully / properly cock, given the short travel of the 9MM PCC bolt.... and it doesn't take much more ramp to mess up cocking.
That USGI profile hammer profile sometimes helps with complete cocking, given that situation.
Pics of the hammer profile and ramp section on the carrier ?
And a few more details on your build, please. Extended 9MM PCC buffer ? What brand 308 carbine recoil spring ?
What specific ammo used ?
Also, it might need a little more break-in. To allow some of the parts to loosen up.
Pic showing hammer profiles and what I mean.