Dummy weapons function mechanically like clones of real weapons, they just don't do the violence part. The idea is that at the objectives, you just run normal FIST-style combat, but when something would be lethal they'd just call "hit" mil sim style. I thought I specified they have full-fat weapons for the open field, and are instructed to switch to the dummies when they enter an objective area. it's supposed to introduce some of that back-foot friction you describe and possibly the opposing sense of "oh, we might need to shred some defenseless guys to stop this actual threat". Either way, the fun here is making the simulation go to heck, and I trust refs and players to make that happen (and quickly). I always try and keep it loose, especially when I'm jamming out a pamphlet.