Thanks for the kind words fellas- very much enjoy your story Mitch.
Suffice to say, the only thing I think I could never see myself doing in combat, where I would "Freeze" is going over the top. The fact that guys did it after seeing the horrors of that is just amazing.
Al- to me, the MG was always there- portability and deployment of the MG was the bigger issue imo. Sometimes simple things can completely change the landscape- take the use of the stirrup for instance (in the middle ages).
Anyway, the MG was always there in the ACW- it was difficult to manuever akin to toting a 7 pounder into a fray. Also, they were aligned to fire straight volleys essentially downrange (with some degree of variance)
With WW1, the MG got smaller, and a team of grunts could carry them and deploy them. Then, as trench warfare settled in, MG nests could be effectively positioned to setup field of intersecting fire which allowed a full out onslaught of murderous proportions.
Great points on the subs and airwar as well- though Al, you are the expert there (WW1 aviation history)