It might be that these problems are not happening due to bad luck with normal pressures, these seem to be generally attributed to excessive pressure spikes due to not using some slower powders as intended or as becomes the recommendation?
It's happened with black, and that's plenty fast.
A report on the Shiloh forum indicates it happened with a hang-fire BP load and it took exactly one shot.
AA 5744 is a fast powder for a rifle.
Successful loads are made for the 45-70 using fast powders such as Unique also. Some guys go as slow as IMR 4064 and seem to do just fine.
