Well...... I've isolated a big cause of the problem....
It's the comp. With the comp off, there is no malfunction. It is definitely sending a sharp impulse that is causing the different latches to hop out of the detent.
IMG_3520.jpg
The unfortunate thing is, now that there is no comp on this 4.5 lb rifle, it recoils the same as my heavily comped FAL. The point of the build was to have an ultra-light near recoiless rifle. Frustrating. I guess the search for a new muzzle device starts now. Maybe a linear comp...since I can't have a powerful comp on the end and have to deal with the brutal recoil that is the 5.56, I might as well direct the blast down range. Or just get a suppressor...
Yay race guns.