Thanks guys. Of course I would keep it to 2 3/4 or 3" shells. I guess my question about the gun handling a magnum load comes from there not being something stamped into the barrel along with the shell length denoting that a magnum shell is acceptable.
The tutorial about magnum vs field loads was also informative.
They have a couple of outdoor ranges in the WMA near Krotz Springs. There is a rifle/pistol range and a shotgun (skeet) range. The skeet range is only open on Thursday (1-4pm) and Sunday (9am-4:30pm). I don't know if the rifle/pistol range has similar times. So far, I've only used the skeet range, with my M2 field, but I do have a Luger that I want to try out on the pistol range.