Thanks for the responses.
Dand,
I did some searches and found info on what you described relative to the .264. In my case the TBBC's mike .257" only at the very base. Go towards the tip less than 1/4" and the bullet diameter has already shrunk to .255". If the plan was for a 2 diameter bullet, they sure aren't leaving a loader much to work with.
Autorim,
I took a fully prepared case with no powder or primer, and seated a TBBC to an overall length of 3.700". I then chambered that round and measured. I repeated for a total of five. They measured 3.676", 3.667", 3.656", 3.658" and 3.656" respectively. The magazine length limited me to 3.630", so I went with 3.630", knowing I was well off the lands. The bullet length is 1.148", the case length 2.840", the neck length .220". This places the base of the TBBC .138" below the case neck, leaving only the .255" diameter portion of the bullet loosely contained in a neck .002" larger.