My first thought on this was that any wax in the bore would be burnt out with the first shot from a centrefire, which would more or less leave you in about the same situation as you'd be in after firing the first shot when using tape over the muzzle. I was briefly intrigued by the idea though. Then I read that comment about "filling in pores" in the barrel steel and that was the end of it. Porosity is just not an issue with barrel steel. The process of forging a barrel makes sure of that. Anyone claiming that this (or breaking in procedures) somehow fills in the non-existent pores immediately marks themself as full of it.
I do use wax on the exterior of my rifles for protection against the elements. I don't wax the bore, and I think I'll continue to use a bit of electrical tape over the muzzle. A couple of extra wraps around the barrel gives a bit spare to re-cover it after a shot. I've been doing this for many years, and it works.
