I'm going to side with NitroX here. Making a rifle out of a shotgun is an all around bad idea unless the "rifle" cartridge is a slug or ball operating at the same pressures as the original caliber. Shotgun frames are not in the same universe as rifles when it comes to action flat and sidewall thickness and the strength that comes with it. The number of bites is irrelevant. The popular idea that a "third bite" is absolutely necessary is nonsense for two reasons. The first is that you shouldn't be converting a shotgun in the first place and the second is that those third bites rarely are fitted properly to make any contact at all when in battery. This is especially true of the cheap Spanish designs that seem to be so popular with the conversion crowd. The fact that they are recommended in a certain book is not a reason to use them or any of the other dodgy methods recommended therein. A little knowledge can be a dangerous thing. I'm sure that no end of people will chime in about how they did it and it works great. I'm sure that they do, right up until they don't. I've seen the results of the hubris of some "eyeball engineers". Leave the engineering to engineers or be willing to educate yourself about all of the areas that apply to your intended project. I'm willing to bet that if some of you guys knew a fraction of what you currently don't know, you'd be scared shitless of your creations.