Tip on the ball joints. When it's being stubborn to come out (and the lowers will) simply pound on the C of the clamp with a hammer while hitting it with impact. Your goal here isn't to drive it out with the hammer (so don't wail on it), the vibration just helps the calmp do it's job (When I first did a job I tried for a long time with my impact and the pressure cranked up to about 300psi, when hitting with the hammer I was able to pull it with just 120psi of air on the impact).
As for me - I should be working on the M416 this weekend, we'll see if that happens...