At the time of the engagement with the LEO in question, where was your firearm? On your own person, in a vehicle, in the hand of another, ...?
Irrespective of the reasonableness of the engagement, let alone the arrest, if they've so far refused (in 10mos' time) to return your property then I'd think making a simple request to the head of the LE organization (police, sheriff?) that your property was taken from you and has yet to be returned, and that you want it back. Inquire about the specific process and turnaround time involved. I'd also ask whether it'll be necessary for you to engage your attorney to get them to release your own property to you. (Can't imagine an attorney would charge much at all, to write a simple letter noting the statutes/ordinances in question.)
That said, in this age of swipe-fast / return-slow, it doesn't surprise me you're faced with a long slog to get your property returned to you.
If you continually meet with resistance, I'd suggest speaking with a competent attorney who is well-versed in getting the municipality (or state?) to cease retaining your property, if indeed they have no lawful cause to still have it.