I recall reading that pentolite manufactured for military use was 60% TNT, 40% PETN, and was due to the PETN content significantly more sensitive than Composition B, but that the military required its high brisance and detonation velocity for shaped charges and related applications. Supposedly more than 40% PETN made pentolite too sensitive to shock, vibration, and friction for safe handling under field conditions. I seem to recall reading somewhere, many many years ago, that a 50-50 pentolite mixture would improve the performance of the device it was used in, but this would make it just too dangerous for applications where the shells, rockets, etc. would be stockpiled for years, loaded on and off trucks and aircraft over and over, etc.