Welcome, welcome to the premier double gun site. You have a nice box lock gun. From an old doublegun shooter/hunter ........ please, please do not open those chokes right now. I have been down that road, many years ago, and regret every choke I ever reamed. You can take metal out very easily, but you cannot put it back to it's original state.
As has been suggested by others, there are other means to open your patterns, those things of which I now avail myself when I want an open pattern for a particular pursuit, which is not that often. Nevertheless, the means are there. Please, wait and shoot your gun a year or two before reaming your chokes.
All my best, SRH
