Interesting, how some of the "larger" cartridge formats jumped around severely while others in the "larger" cartridges seemed very controllable.
Loved the H&K MP5 and the FN P90.
Haven't taken too many select-fire rifles out for a spin, myself. A few, but it's been years. There are the occasional "machine gun shoots" that I've been to, but I do those more to see the range of equipment than to spend boatloads shooting them.