Regor, I have not squeezed the mag bodies. Not familiar with the details there.
I have tried round nose, and truncated cone, in both 9/40.
Same issue. The Top round surfaces with a gap between it, and the round underneath of it, then gets pushed straight into feed ramp. Spring appears to maintain adequate pressure though.
The reliable feeding, when loaded down to 19~20, didn't draw me towards the top double/single junction, should it?