My simple understanding, not backed up by hundreds of animal carcass dissections and Bayesian statistics, is that the same frontal area of expanded bullet creates a bigger permanent wound cavity going through animal tissue when it is going around 10% faster (i.e. a 110 at 3400 as compared to a 130 at 3050). I could be wrong though. The 110 gr .277 bullet started at 3400fps is still going at 2400 fps at 400 yard according to ballistic calculators at my altitude of 7200 ft. It expands pretty well at that velocity still.
I could be wrong but my conception is that with the X bullets the cavity is the same size say in the 120 and 175 grain bullets, Connie or someone else at Barnes confirmed this when they were fairly new. The 120 going faster will create more of a secondary wound channel due Roy Weatherny's favorite term hydro static shock. The slower heavier bullet acts more like an arrow with a similar primary (permanent) wound channel but less of a secondary (temporary to various degrees) wound channel. The faster bullet is more likely to shed petals and the shorter bullet would have a greater chance of tumbling. I believe I have observed this when a light bullet went through shoulder bones, but this is an unusual occurrence.
I will be shooting the Lehighs this year to see if they are more effective. But I have never lost an animal with monos so how much more effective can they be? I believe the theory and reports from animal control work seem to support the effectiveness of the petal shedding monos.
