I have been hit by SIM ammo. It hurts. The whole FPD series is to train techniques based upon experience. It does that very well and it is FREE!
Your not the only one that has taken Sims rounds.
The more realistic the training becomes the higher the chance of injuries become.
Breaking bones, hurting your students, causing work comp claims because of training his highly frowned abound.
Being sue for causing injury isn’t good either.