FWIW I built my 20 BR with the thoughts of it not lasting because I *knew* it was OB...ALRIGHT ACKMAN!!!! I did talk to one guy with a .20BR and in less than 600rds his barrel was toast, junk in other words. Can't see where this other case would be any different, to much powder to small a hole.
I am interested in your results/article. FWIW I shoot a 20 Habu Shrew (20-221 Imp) that has both radius shoulder and a bud that has a std 20-221 Imp. Although it is not a scientific test from as near as I can see there seems to be very little if any difference between the radius and non radius shoulders. Same components = near the same velocity. Both of them get an unbelievable velocity and accuracy with the 32 v-max making it a better high volume PD round than my 20 BRI hope to complete an article on it with load and pressure data this summer.