Kinda strange, guy asks for and advice and in the same time says what he wants. If you are new, then how do you know what you want? Why shorts? Why semi-auto? Who said it has to be stainless? I mean, with such presumptions you may as well buy what you THINK you want and forget about all the advices here. If you get this "bug" then trust me, you will have more then one rifle anyways. Maybe a dosen.
Get used anything for 100$ and shoot a lot, shop around later, carefully and with experience.