So, I recently picked up a Browning A5 in 12 GA and I want to chop the barrel to get rid of the polychoke.  Who do you recommend around St. Charles that can cut the barrel and thread for chokes?

Eagle eye in Wentzville.

The gunsmith there recently did a barrel thread on a sub 2000 for me.

Outstanding work and quick turn around.

When I've needed barrel work, I boxed up the barrels and send them to Mike Orlen in Massachusetts

Turn-around is fast and he does good work.

BTW, why do you think you want choke tubes? Is this going to be a bird hunting gun or a social-purposes gun? Are you going to shoot that gun beyond about 35 yards? With what size shot? A cylinder bore will do just fine for almost anything a person could ever imagine using a tactical shotgun for. An A5 is going to be pretty useless for a lot of things that you'd need constricted chokes for (i.e. waterfowl hunting) since you can't use steel shot in it. . . . If you're not going to thread it for tubes, any hack can cut off the barrel and install a new site. I wouldn't send it off for that. If, on the other hand, if this is going to be a sporting gun and you actually have need for choke tubes, I wouldn't trust the job to just anybody. You'll surely need thin-wall tubes and those are easy to booger up.

FWIW, I think that people put WAY too much emphasis on choke tubes. With modern plastic shot wads, choke just isn't that important for the kinds of shooting most people do with a shotgun. An open (or relatively open) choke barrel works great.

I recommend Eagle Eye and CnS Metal Werkes. CnS has the tool to thread for remington chokes, I used it on my own gun (I used to work there before moving to Germany).