b) yes there are marks on the primer the firing pin has been lubed as per manufactures instructions (very light film of CLP) nothing into the firing pin channel though.
I have never lubed the firing pin on an AR. Ever. Not even once.
Not to 'doubt' the manufacturers instructions, but try running the firing pin dry. Sounds counter intuitive but sometimes lube on the firing pin causes problems.
If you can get a hold of a 'no go' and a 'field' gauge, I would try those to check the chamber, just in case. If it's firing 90+% it's probably not the issue but it's not a bad idea to check.
Its probably the hammer spring, though. I recall them having issues with a batch(es) of springs, so it could be just slightly under-powered. If you have a friend with an AR and you feel competent enough to do it, swap out the spring and see if the problem goes away.
Or you can contact NEA and fill out a warranty ticket.




























...






















