you had better do your homework. your fixed bbl has a .723 bore. optima chokes are designed for a .733 bore. if someone is dumb enough to do this and you are dumb enough to shoot it, i sure would like to watch from a distance when the gun goes off
I just had my unsingle barrel tubed by Carlson's, excellent job, shoots great and fast turnaround, i had three extended tubes which comes with a deluxe choke tube wrench, + shipping $150.00. smokum, Big Jim
If you really want an Optima barrel, check out Hi-Grade Shooters Supplies, link above. Or Joel Etchen (www.joeletchenguns.com) sometimes has Optima barrels for sale. These will fit your 682 receiver with a little fitting.
If you really want "YOUR" barrel choked, you need to ask for thin wall chokes.