Absolutely correct, sehr geehrter Herr Tom. Wir warten auf Ihre Anträge. 
Thanks.
So, what do we have here:
Yours
tom! 
Well, it seems to me that we actually have here only a nice little warning sign, my dear Mr. Tom. Perhaps we do need some additional level of authorization? 
Hm, I don´t know why, this should work.
OK, now from my webspace:
Well, it certainly looks like the Japanese Army Type 2 Antiaircraft Machine Cannon, my dear Mr. Tom.
Hi.
Sorry, my computer broke down last week and it took some time to get my old Win98 PC running.
Your answer ist correct, so it´s your turn again.
Yours
tom!
Oh, my goodness! You have my heartfelt sympathy in your sudden affliction, my dear Mr. Tom. I do know what all that means… That happened to me as well! 
Well we have to start this time with something… well…bigger and a little bit more powerful:
As usually, honorable ladies and gentlemen, we are anticipating your kind offers!
#67.
Best Guess: one of the Brit coastal guns in Singapore, before WW2 began.
Reasoning: patterned on the 4-inch turrets of the late WW1 “Tribal” class destroyers.
Also, afaIui, Brit coastal guns at Dover, for eg. were casemated, not turreted, as were the french guns at calais.
Alas – no, my dear Mr. Uyraell. Those guns were not as BIG as this sturdy fellow, which actually continuously fired from 1941 to 1944!
My dear Librarian, my thought now as to this pic is a decidedly random, odd, yet intuitive one.
Perhaps this weapon is not Brit at all, but rather, one of the guns salvaged from the Goeben or Breslau after WW1, and emplaced by Turkey thereafter?
Most likely I’m wrong in My intuition, but then, I’ve never seen an image of those weapons. Some vague hint in the back of my memory suggests the salvaged weapons were 9-inch naval rifles, though I have no more than said hint to go on.
Kindest Regards, Uyraell.
Bingo, my dear Mr. Uyraell! Undeniably, our big mystery shooter is not of British origin, and after the WW2 even some nuclear artillery shells were produced for that brawny cannon.
Of course, numerous other tips are also available!
It would seem, my dear Mr. Librarian, that I have to go out on another admittedly shaky limb.
Kuivasaari, is My next guess, though I see no images of the actual turrets on the site I’m looking at.
At any rate, this exhausted brain cannot currently conjour a better asnswer.
Kind Regards my friend, Uyraell.
Well, I’m a bit stumped, to tell the truth, so I’m having a blind guess.
The gun mantle visible in the picture is not quite right for the type, but I must eliminate this possibility, since there seems to be an emphasis on the word “big” in your posts, my dear Mr Librarian:
40.6 cm Schnelladekanone C/34 of the Battery Lindemann.
Later edit: Scratch that, I found our mystery cannon!
406mm Soviet B-37 Battleship cannon in test mount at the Rjevskiyi firing ground.
This massive cannon was originally designed in 1936 for a battleship programme that never materialised and took part in the defense of Leningrad from 1941 to 1944. It can still be found there, but is now in danger of being scrapped.
Since our Mr Librarian hasn’t signed in lately and I am 100% positive of the correctness of my answer, please allow me to post a new enigma, in order to “keep the ball moving” as it were:
Dear Mr. Wingsofwarth,
for me it seems a japanese field howitzer or a mountain gun, but I really cannot identify the exact type.
Is it corrert?
TGR
Mr. Tiger, I can assure you that the howitzer in question is not in any way related to the Empire of the Rising Sun but instead must be sought after in a country that lies further west. I can provide you with further clues, should you need them, but I will remain silent for now, since our esteemed Mr Librarian has joined the game once more.
o.k.
I have already realized my faults.
But I still cannot identify.
The general layout is very similar to Krupp (96M) 7,7 cm Field Gun, but the gun itself has larger caliber and shorter too (so more likely howitzer than gun)…
I have to make some additional research,
Regards
TGR
Faults? My dear friend, I must congratulate you on your keen eye, since you are certainly on the right track - this mountain howitzer certainly originated at that esteemed establishment, but the calibre is somewhat larger…
I give it up!
That should be a baltic/polish/german instalaltion of a 10 cm short-barelled gun to the mentioned carriage.
In my archive no such data (although the Austro-Hungarian 10 cm GH is quite similar) - so - let the others try it!
TGR
My dear Mr. Wingsofwrath … I think the image you posted is of a Japanese Army mountain Howitzer, Type 18, from (iirc) 1927. These were among the earliest guns employed in Manchuria, and if stories are to be believed, were still in use as training pieces by Chinese forces in the 1950’s.
Kind Regards, Uyraell.