The malfunction seems to be a magazine and I agree with the other posters that is is necessary to identify your magazines and test to verify that the malfs occur with a certain individual magazine.
What is the exact nature of the malfunction?
A small amount of lube is required on the bolt carrier rails, but too much lube doesn't necessarily contribute to reliability. If it's not short stroking, more lube won't help anything. I run mine almost dry, and if in extreme cold weather or dusty conditions, they MUST be run almost dry.
A little dry lube won't hurt, but a USGI magazine in good condition should need no lube and I run mine clean and dry. The MagPul magazines and followers are decent units, but should not be necessary to make the rifle function correctly. I would say that there are very few aftermarket magazines that are 100%.
As far as pierced primers go, your firing pin is likely the culprit and it is either protruding too much or is too sharp. Once a few pierced primers are experienced, the tip will usually become eroded, ragged and sharp(er), leading to more pierced primers, so it probably should be replaced anyway. Remove your bolt carrier group, push the bolt back into the bolt carrier and look at the tip of your firing pin. Without a protrusion gauge, it's tough to tell if it's protruding too far, but the problem is more likely that it's sharp. If the end is not smooth and round, I'd suggest getting a replacement firing pin for $6-$8, and it's not a bad idea to have a spare anyway.
