OP, are you testing the trigger or the new hammer spring?
So I have a AR10 that I replaced a Timney 4lb ar10 trigger and “high mass” hammer with an AR15 3lb trigger with a the standard or low mass hammer. I am pretty sure the new trigger will detonate a civilian LR primer but not sure about mill spec primers because the primer cups are thicker. I will test it in the morning.
Thanks for all the ideas.
Guns don't kill people, gun free zones kill people.