If charges are filed against you as a result of using your firearm you are likely in deep po ("DP") .
Once in DP you will likely be arrested then need to get out on bond.
To get out on bond you agree to the conditions the court sets - usually the court sets one of the conditions as "Do not possess, carry or have access to weapons."
You will either accept the court's conditions of your bond and be released or not.
If you accept the conditions of your release then violate them you can be charged with a separate offence.
Backups of guns are a good thing for dryfire, having a gun go out for service or having the ability to use one as a test platform for different triggers, sights and safety configurations.
But after a shooting in which you are charged?
You may not be ineligible to possess firearms under federal law, but if the court says "no guns for you" it is no guns for you.