rear drum brakes issue

needs some help, 8-3/4, rear drums, everything new.

the drums refuse to rotate when I tighten the wheel down. if I loose the lugs slightly, it will rotate, but when I tighten them down, movement / rotation stops. It does it on both sides the same with the wheel tire off (so it is not a tire rub). I have tried......

removing drums and re-adjusting the brakes

new, different drums

small spacer / shim between drum and axle flange

checked the backing plates...zero sign of contact with drum

checked the drum... zero sign of any contact with backing plate or anything else (brake shoes)

I'm stumped and looking for ideas.....all welcome.