Punch cutter + big ring = tunneling?

I have no more burn problems with large RG than I do with small RG, but I don't have many problems with burn at all. Why don't you try and cut the cap off with a knife and see if you have the same problem as you do with a punch? What kind of cigars are you smoking that tunnel? If they are CBID specials, I can tell you without a doubt it's the cigar. If you have the same problem with higher end cigars, I would suggest checking your RH level (probably fine, but have to ask), and making sure you are getting a good and even light (everyone screws this up from time to time). Those two factors affect the burn much more than anything other than the quality of the roll (weak/new torecedors make inconsistent cigars), just MHO.