ORIGINAL: bradfordkay
Joe, by "small calibre" I was referring to the 25-40mm AA, not the lighter machine guns. Were those also ineffectual above 6000 feet?
Ah, ok, in general I would use "small calibre" to refer more to the sub-20mm AA heavy machine guns and then the terms light AA, medium AA and heavy AA to refer to the "AA guns".
First, the Japanese landbased 40mm AA gun does not show in most sources and one in which it does show indicates that the inscription on an example captured by the Allies reads "Vickers-Armgtrongs 1931" and this source thus guesses that the weapon may have first been captured by the Japanese (perhaps from the British). So we should probably discount the 40mm weapon in general landbased Japanese service until someone can so up with production informtion, if any exists.
As to the 25mm weapon this, of course, was a naval weapon, designed and built for use at sea. There is evidence however, that "later in the war" some of these weapons were used ashore. And BTW I am assuming we are talking about landbased flak in this thread. The seabased flak uses completely different code etc. So again, I am assuming we are talking about strickly land based flak here. The range of the Japanese 25mm weapon is given as being just short of that of the German 37mm weapon (flak18/36) ... for those light/medium guns that I do have maximum and "effective" air engagement ranges, the effective range is usually given as 40% of the maximum. Also note that most light and medium guns, in either Japanese or German service fired not under director control. But all this boils down to an effective verticle range for the 25mm of 5,600 feet. Of course, how many 25mm weapons should be introduced to the naval base forces in the game and on what date ? Those questions would require more looking.
EDIT: it appears by your comment about the German 50mm guns are attesting to the fact that the 25mm were not effective at higher altitude.
The German 50mm flak41 had an effective verticle range of 18,374 feet versus the 37mm flak18/36 effective verticle range of 6,562, so a considerable "extention" into the ranges covered by the "heavy" flak weapons.
People have pointed out that some are missing from the AA units, but I wonder if they were also missing from the table of organization in real life as well. Many units served in the theatre without it's full allocation of equipment. This is not to say that I don't believe that they should get them, I am wondering if they were left out for a reason (such as not available to those units even though they were authorized).
If the Japanese spent a lot of time updating their printed TO&E's during the war, I haven't seen much evidence of it, especially for naval "support" units like flak and shipping companies. The triple digit IJN baseforces we have in the game, seem to be an amalgamation of real world units which include independent naval flak companies (of which there were a total of about 200 in existence during the full war), naval guard/defense forces (of which there were about 120 - though in the game we seem to get them twice, both in the 3-digit base forces and separately) and shipping units, which included shore based warehousing units, port based loading and unloading units (including lightering as well as crane operation) and port construction units. Apparently the designers decided to make our lives a little bit simplier by amalgamating these various units into the 3-digit naval base forces. This area could probably use a fresh look and maybe one of the modder communities will do so. But within the current stock OB, the place to add in any 25mm guns that you'd like to add, would be in the named baseforces or in the 3-digit baseforces as the naval flak units appear to be already combined into those units.