I have wondered the same myself - some claw bases are dovetailed pretty deep into the receiver ring - such as this:

I know... crappy photo!

My ony thought is that the barrel threads into the ring about halfway, so for a ring to crack or fail there would have to be a greater failure in the chamber or bolt face. IMHO
There is a lot of "meat" around the bottom bolt lug when the bolt is closed - perhaps that is enough(?)