Those Snap2it things are great for fishing....
If a tug doesn't seat it, grab it at the KO and pop it in with a pair of needlenose or Knipex channel locks.
I too have come across different brands of MC that the conductors will pull out of. And occasionaly some that is still soaked in degreaser from the factory, so the whole inside of the cable is 'lubed', you could easily pull out 20'. One place I go to has the "cleanest" MC around (when I stock the truck I go there), no blackened hands....