I am a fan of Gordy's alignment method. I think it is in theory the best way to do it.
That said, I have a video by Richard Franklin of Richard's Custom Rifles "Metal Working for a Rifle Smith" that was not very expensive, but it sure has a lot of information chambering and a bunch of information on receiver truing and bolt lug truing.
IMO, get all the video's you can, watch them all, also recommended is getting a book or two.
Also highly recommended search this and the Practical Machinist Gunsmithing forums looking for threads on chambering and receiver truing. A search on Gordy Gritters will find a bunch of information and links to very good web sights. Copy/paste the pertinent discussions and other data into an MS-WORD document under suitable headings and you will soon (I spent maybe 16 to 20 very pleasant hours doing it) find you have created your own 130+ page book based on the experiences and techniques of practicing gunsmiths. I did that. It is very informative. It will also give you a terrific framework upon which to hang the data you acquire before and during chambering experiences.
