ORIGINAL: KodiakArcher
Any time I've run into this it's been idler/cam lean. The worst was my Old Glory which I couldn't remedy until I slapped a damn whacky basket on it but I know that's just masking the problem, not solving it. I put the QAD on my old UltraTec and it's worked great there.
Only thing I haven't checked was idler lean at full draw. Have to figure out how to do it.