Absolutely, Propsculptor is correct. Some advice, though, don't get too crazy with your first projects. Start small, some open-faced molds, perhaps some simple two-piece molds, then expand from there. Diving into something like a full-sized prop gun will probably cause you a lot more frustration than anything else.
Many people have this preconceived notion that you can drop anything into rubber and cast a copy. In truth, you have to break the model down into castable components, being mindful of undercuts and things that could cause potential damage to your molds.
Then you have to consider either vacuum or pressure casting to ensure you remove or minimize air bubbles from your process.
A lot of things to consider and learn, but anyone here who casts will tell you that pulling that first perfect part from the mold is still a rush - no matter how many times you've done it.