since I'm converting to Flextab capability and swapping these parts out I'll probably just replace the spring at the same time. Based on the issue and what youve said, really this seems like the only possible variable. If that springs bad or gunked up the carrier will be pretty lifeless. It's a 30 year old gun and has probably never been swapped out and I'm inclined to believe it was bad because it was spotless and well oiled when the issue was occurring.
Strangely, the gun started off functioning perfectly and worked its way into acting like this. Maybe the spring went bad right then and there..