That’s actually a really good point.
At what point does the barrel barrel become so ridiculously long that it’s not a handgun anymore?
It’s not about barrel length, because you can have a 10/22 with a 7” barrel and it’s still NR.
As this is rimfire, barrel length shouldn’t matter and it should actually be above the overall length of a non-restricted firearm.
If it’s close to the overall length, then why not go the extra mile and make one with the most absurd barrel length required to make it NR?