all the way thru, can be "held" for a 9" long 223 suppressor. The larger the hole in the baffles, the more blast and noise can get-past the bullet and out of the can. The tighter the tolerance between the baffle hole and the OD of the bullet, the closer to being perfectly straight the can must be (and STAY) with the barrel. Many commercial can makers put a .30 cal hole thru their 223 cans. That is one of the reasons that they aint very efficient.