I would like to understand the real objective. Is it a need or a wish? Are you an enthusiast with spare cash to spend on an expensive project and not worry if it flops? If that is the case, you have no limitations. If the objective is to be absolutely successful, then you are better off contacting a gunmaker first & discussing your wish list. The gunmaker would guide you the options that they can guarantee.

If you are planning a home made project, you will have to take the risks of possibly losing money.

I am with bonanza on this one.