Yes, of course. You said "if nothing else sticks." If nothing else sticks then the only thing the court has on the person is possession of a firearm.
If possession of a firearm is the only thing they were (able to be convicted of) doing wrong, why do we care if they have a firearm?
If they were arrested, tried, and convicted of some violent CRIME, put them in jail for THAT.
What you seem to be saying, and what I was hinting at, is that folks generally want to say that these people should just plain be in jail, period. With no further wrong-doing on their part, we have the excuse for putting them back in jail because they were caught with a gun.
I'm saying, if they're up to no good (i.e. some violent crime), go ahead and lock them up for it. If they aren't then the gun charge is just a cheap and easy excuse to send them away which is what you really wanted to do all along, anyway.
"Hey, did that guy hurt someone, kill someone, rape, assault, threaten someone? What?"
"No he wasn't bothering anyone, but we caught him with a gun."
"Oh, thank god, we can go ahead and lock him up for that! I thought he was going to WALK!"