It's a little hard to describe it. With automatics also it's quite easy to kink the spring just after the bridle too*, but here goes.   Get the spring started in the barrel, like the first turn in, as would feel natural (i.e. just do it). From there, you want to manipulate the spring, turning the part out of the barrel around by half turns until that bit will drop in, continuing until the spring is in. The important thing is to not stress the spring. It works with watches because almos