Let’s consider the revolver since he ordered it about six weeks before he ordered the rifle. It does seem reasonable that if he intended to use the revolver to shoot Walker, he most likely wouldn’t expect to get away with it because using a revolver would typically need to be at a relatively close range with other people being present. Under those conditions using a separate P.O. Box makes less sense.
However, it seems to me that by March 12, 1963 LHO had probably devised his plan to shoot at Walker with the rifle at night from behind the backyard fence and his expectations of getting away with it would have been more reasonable. In fact it appears that he planned to do just that (get away with it). And he apparently delighted in learning from the news accounts that the DPD apparently didn’t even consider that anyone would try to make an escape from the scene via public transportation. Under these conditions, using a separate P.O. Box would seem to me to make more sense. He wouldn’t need to maintain the P.O. Box any longer than it took to obtain his rifle. So the expense would have been minimal and prudent in my opinion.
Whether or not it would have made sense for him to get a second PO box to receive the rifle, the fact is he didn't so that becomes a moot point. There is ample evidence he ordered the rifle from Klein's, ample evidence he received it, ample evidence he fired it at Walker, and ample evidence he used it to kill JFK.
Oswald's note to Marina indicated he thought there was a real possibility he would not be coming back after killing Walker. He gave her specific instructions as to what to do if he did not.
The curious thing is why he missed Walker at such short range. I've read the suggestion Walker might have leaned over just as Oswald fired, ala The Day of the Jackal. I think the answer might lie in the fact it was such a short shot. The Carcano's fixed sights are zeroed for 200 meters which means at that range it would shoot high if Oswald didn't make an adjustment in his aim point. The scope was adjustable but if Oswald didn't adjust it, the same problem would have occurred. It's all academic. Oswald missed and likely would never have been identified as the assailant had he not killed JFK.
