Inferred from all of the above, the gun platform isn't really all that important so much as adding skills.
So, figure out what you want to learn that's different from what now can be done. THEN worry about the gun platform.
Back about twenty years ago--if not more--I read that guys at Fort Benning became proficient enough at Point-and-Shoot that they could hit a tossed aspirin with a BB gun. There's a skill that is way above average, and certainly inexpensive to learn.