I don't know where to find factory 6BR ammo. They certainly don't have it at Wal-Mart! lol

I am getting roughly 15% misfires.

I have had the bolt apart, I didn't change the protrusion, as I didn't know the spec at that time.

Are the adjustable assemblies more desirable than the new style?

There are a few guys on accurate shooter.com that have had similar problems that were fixed by beefier springs.
Please tell me why a bigger spring is a bad thing.