JB.
Swaging a bullet with GG is just about lost and forgotten.
At a time past there were a few swage press and die makers that offered a swaged GG die, Like Lachmiller and Herters and I think Hemp that made a collet die for the swage presses. It's a shame that that is getting to be a lost art.
But you can get around the collet die by cutting the grooves with a lathe or you can roll them with a tool that I use.
Or do it like I swage them.