I installed a standard, untuned RRA NM trigger in my old Bushmaster lower. All safety checks are passed, but the letoff is a consistent 39 to 40 ounces. That's right, a 2.5# trigger from "drop in" parts.
Should I be pleased, or concerned? I have not tried firing the weapon with live ammo yet, but in dry firing at least 40 times, the sear catches the hammer every time as the disconnect releases it.
You adjust the trigger pull weight by the hammer spring tension. If the FCG passes the checks, then all is fine.If you start to have light primer strikes, then you may have to install a new/stronger hammer spring, which will increase the trigger pull weight.
In regards to the trigger alone, the real factor is if there is any creep after you hit the second stage tension point. It should be first stage creep, then hit the wall (second stage), with the feel from that point like you just broke a glass rod to release the hammer.
When RRA triggers are worked over/custom tuned, its the second stage creep that is removed.