u/Regular-Location-444

I have never printed an airsoft rifle before, and was wondering how hard would it be to make a custom bolt action? The idea is that it would be shell ejecting, and would use a gas revisor that sits in the grip and pipes through the bolt and through a shell with a bb at the end to fire it. The question is: what do I need to buy to achieve this? and is it at all realistic to keep it under $100?