Hammerli 208s Re-assembly problem

When I try to draw the slide onto the frame, the stud that retains the Recoil Spring Guide Rod in its channel below the barrel rotates outward blocking the installation of the slide. Many retries yield the same failed result. Any hints on how to overcome this snag? Thanks!

Jeez, no help! O.K., I took a 1/8 inch punch and holding it perpendicular to the axis of the bore, used it to retract the recoil spring and guide rod, then dropped the slide on and withdrew the punch. Hillbilly mechanic meets Swiss engineering.