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If the police saw him point the gun at you, I suppose they could have arrested him right there.
You likely could press charges against him for assault, either criminally or civilly. Just by pointing the gun at you, if that put you in fear of your life or safety, then he assaulted you. Should you wish to sue him in civil court for assault, you may be able to win a monetary judgment. Seek advice from a local attorney on this one. As for the potential criminal charge, you might be able to have him face a criminal penalty of jail time, probation, and/or a fine.
Frankly, I'm not sure that either of those options is the best use of your time and resources at this point, especially if the situation has blown over and is behind you. But it sounds like you have every right to pursue either or both of those avenues if you wish.
The best approach likely depends on what you perceive the future holds:
If he admitted to pointing the gun at you, but he was not arrested, perhaps criminal charges are not very likely. Your best legal options, should you decide to pursue anything, may be for a civil action for assault. Again, it's best to consult with a local attorney who is familiar with your state's laws on these types of things so you know up front what elements would be necessary to win such a case and see if it's worth it to you.
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