Looks like a bit too much radius. Find your center of the call opening. So if you have a 6" opening put a mark at 3" in the center. Now mark the ends of the opening. Assuming the top of the box edge is straight measure about 1/8" down make a mark. Do the same on the other end and make a mark. Now draw your raduis making sure it is no more than 1/8" below the center of your opening. That will give you a workable raduis. You can draw that out on some cardboard and then cut it and use it for your template on all your calls. No Keekee in the front you took too much wood out.
Larry