Light primer strikes - fail to fire

[grayfox]

Upon disassembly, I found an excessive amount of oil and carbon. I would like to think this, combined with the below freezing temperatures, slowed it down enough to not ignite the primer.

Any other thoughts?

Only other thing that comes to my mind is -- and this is from a different rifle, bolt-action not grendel -- this other 7-08 had a titanium firing pin, lawyer-like to lessen slam/srop fires, instead of steel. That, combined with low temps and some oil (Rem oil in fact) in/around the bolt/FP, led to 4 light-strike nonfires in a row while I was on stand with a deer in my sights. I think all AR FP's are stainless so probably not an issue here, but it does illustrate how a firing pin can be slowed down to give light-strikes.
btw, I ditched (traded in) that rifle and went with another mfr, with steel FPs I could trust.