I thank you for correcting my attempt at posting the image, Ron; much appreciated and I now know how to do this correctly moving forward.
As far as this marking being potentially some form of AIC I do think this is possible and again thank taber 10 for the tip. I have attempted to follow up in this regard, but have hit somewhat of a brick wall. As I am sure that many of you here are well aware the AIC was a sub-set of the SNL [Standard Nomenclature List] that was utilized by the U. S. Army’s Ordnance Corps from the 1920’s until 1958. In attempting to apply taber 10’s advice concerning the five “letters”/characters that make up this marking/code and spending a few more hours of research time on this project, I now better understand what each of the five characters represents, again information that I am sure is not new to many on this forum [but it is to a fledgling researcher/historian such as myself]. The first character consists of a “letter” and represented the SNL group; the second character represented the SNL sub-group and was usually a number. In my case example these first two characters are “Z2.” In examining what little documentation I could find on this from Ordnance materials generated during and just after WW II, the group “Z” SNL group referred to “material”, more specifically captured “foreign material.” When the two characters are put together as Z2 this specific group/sub-group was representative of “major items and major combinations of Japanese materials”. However, this makes no sense to my specific research project area as the ammunition in question was/is not Japanese related, which leads me to believe that the designations I have been following and attempting to use to decipher the WCC box marking pertain only to WW II supplies, but I could be wrong. As a historian treading carefully into this morass I will admit little to no knowledge about this subject matter, which is why I have approached the learned members of this forum for any potential help. All I do know is that the WCC had 4000 of these wooden shipping boxes/crates constructed to hold and ship this ammunition.
As far as the remainder of the marking is concerned - the letters AJX - I have not been able to come up with anything. As I understand the SNL designations, the third letter in the five group character was supposed to indicate the “weapon model,” the fourth letter the type of ammunition, and the fifth and final letter the packing method or container being used to transport this same ammunition. I remain lost and admit that this might just be the old needle in a haystack problem but I do thank members of this forum for taking the time to read this posting and offer what help they can.