Rivet the rear spar together remembering the flush rivets on the lower rear spar.
It was a challenge to use the squeeser on these rivet which secure the VS-410. THe best solution for the flush rivets is to use a rivet gun and bucking bar. Works very nicely.
There was some marking of the primer on the faxctory head side, but you can see the primer remains intact - indicating that the priming job has been good.
