Hi uboatfan, Glenn et al,
The gun in Belgium looks to be an ex U boat gun, probably removed from a type IX in 1943 and put into use by Rommel in his attempt to shore up the Atlantikwall. From the pictures it has been modified to have seats rather than U braces. It has a foot brace in view and I would suspect that it may well have a foot operated trigger. One problem though, it will be impossible to measure the barrel length, due to the way it is displayed.
There are some 10.5cm gun around Europe, but be careful, as most of them seem to be ex surface ship guns, with a different mount and barrel so are unsuitable for comparison measurements. These guns are distinguished by having 2 rings on the barrel (see photo) and there is no guarantee that the barrels are the same length. There is a U boat 10.5cm in Duxford at this time, but it is a WW1 gun.
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[/size]Glenn, I have sent a message to Eduard about the scale issues.
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[/size]Regards
[/size]Jon